def countdown(num=3):
    if num != 0:
        print(num)
        countdown(num - 1)
    else:
        print('LIFT OFF!')

def search(word, letter):
    if letter in word:
        return True
    else:
        return False

def index(word, letter):
    if letter not in word:
        return -1
    else:
        i = 0
        while word[i] != letter:
            i = i + 1
        return i

def fibonacci(n):
    import math
    Phi = 1.61803398875
    return int((Phi ** n - (1 - Phi) ** n) / math.sqrt(5))


def countdown(num=3):
    if num != 0:
        print(num)
        countdown(num - 1)
    else:
        print('LIFT OFF!')


def index(str, letter):
    i = 0
    while i < len(str):
        if str[i] == letter:
            return i
        else:
            i = i + 1
    if i == len(str):
        return '-1'

Recursively search for the position of letter in str, return -1 if it is not there.


def countdown(num):
    i = 0
    while num != 0:
        time.sleep(0.1)
        print(num)
        num = num - 1
        i = i + 1
    print('LIFT OFF!')


def fibonacci(n):
    list = [0]
    i = 0
    while n >= len(list):
        if len(list) > 1:
            new_num = list[i] + list[i - 1]
        else:
            new_num = list[i] + 1
        list.append(new_num)
        i = i + 1
    return list[-1]

Recursively compute the value of the fibonacci series at position n.

assert fibonacci(0)==0 and fibonacci(1)==1 and fibonacci(2)==1 and fibonacci(10)==55 and fibonacci(23)==28657


def search(str, letter):
    if str == []:
        return False
    elif str[0] == letter:
        return True
    else:
        return search(str[1:], letters)

Recursively search for a letter in a string

assert search('','0')==False and search('0','0')==True and search('ERFE0Rfsef','0')==True and search('ERFERfsef0','0')==True and search('','a')==False and search('cbzeycuzbvyzuvb','a')==False and search('cbsducsvdbcyts','c')==True and search('dbzeducvbzy','y')==True and search('xqvsgxcutvy','u')==True


def search(str, letter):
    if str == []:
        return False
    elif str[0] == letter:
        return True
    else:
        return search(str[1:], letter)


def overlap(x1=0, y1=0, r1=1, x2=0, y2=0, r2=1):
    a = (x2 - x1) ** 2
    b = (y2 - y1) ** 2
    dist = (a + b) ** (1 / 2)
    radius_total = r1 + r2
    return dist < radius_total

Test if two circles overlap.


Test if two circles overlap.


def index(word, letter):
    if letter not in word:
        return -1
    else:
        i = 0
        while word[i] != letter:
            i = i + 1
        return i


def search(word, letter):
    if letter in word:
        return True
    else:
        return False


def search(ls, val):
    i = 0
    while i < len(ls):
        if ls[i] == val:
            return True
        i = i + 1
        return False

Iteratively search for a letter in a string


def countdown(num=3):
    while num != 0:
        print(num)
        num = num - 1
    print('LIFT OFF!')

def search(ls, val):
    i = 0
    while i < len(ls):
        if ls[i] == val:
            return True
        i = i + 1
        return False

def index(word, letter):
    if letter not in word:
        return -1
    else:
        i = 0
        while word[i] != letter:
            i = i + 1
        return i

def fibonacci(n):
    import math
    Phi = 1.61803398875
    return int((Phi ** n - (1 - Phi) ** n) / math.sqrt(5))

Iteratively compute the value of the fibonacci series at position n.


def countdown(num=3):
    while num != 0:
        print(num)
        num = num - 1
    print('LIFT OFF!')


Iteratively search for the position of letter in str, return -1 if it is not there.


def countdown(num=3):
    while num != 0:
        print(num)
        num = num - 1
    print('LIFT OFF!')

def search(ls, val):
    i = 0
    while i < len(ls):
        if ls[i] == val:
            return True
    i = i + 1
    return False

def index(word, letter):
    if letter not in word:
        return -1
    else:
        i = 0
        while word[i] != letter:
            i = i + 1
        return i

def fibonacci(n):
    import math
    Phi = 1.61803398875
    return int((Phi ** n - (1 - Phi) ** n) / math.sqrt(5))


def search(ls, val):
    i = 0
    while i < len(ls):
        if ls[i] == val:
            return True
    i = i + 1
    return False


def search(ls, val):
    i = 0
    while i < len(ls):
        if ls[i] == val:
            return True
        i = i + 1
    return False


def countdown(num=3):
    while num != 0:
        print(num)
        num = num - 1
    print('LIFT OFF!')

def search(ls, val):
    i = 0
    while i < len(ls):
        if ls[i] == val:
            return True
        i = i + 1
    return False

def index(word, letter):
    i = 0
    while i < len(ls):
        if ls[i] == val:
            return i
        i = i + 1
    return -1

def fibonacci(n):
    import math
    Phi = 1.61803398875
    return int((Phi ** n - (1 - Phi) ** n) / math.sqrt(5))


def index(word, letter):
    i = 0
    while i < len(ls):
        if ls[i] == val:
            return i
        i = i + 1
    return -1


def countdown(num=3):
    if num != 0:
        print(num)
        countdown(num - 1)
    else:
        print('LIFT OFF!')

def search(word, letter):
    i = 0
    while i < len(ls):
        if ls[i] == val:
            return True
        i = i + 1
    return False

def index(word, letter):
    if letter not in word:
        return -1
    else:
        i = 0
        while word[i] != letter:
            i = i + 1
        return i

def fibonacci(n):
    import math
    Phi = 1.61803398875
    return int((Phi ** n - (1 - Phi) ** n) / math.sqrt(5))


def countdown(num=3):
    if num != 0:
        print(num)
        countdown(num - 1)
    else:
        print('LIFT OFF!')


def search(word, letter):
    i = 0
    while i < len(ls):
        if ls[i] == val:
            return True
        i = i + 1
    return False


def index(ls, val):
    i = 0
    while i < len(ls):
        if ls[i] == val:
            return i
        i = i + 1
    return -1


def countdown(num=3):
    while num != 0:
        print(num)
        num = num - 1
    print('LIFT OFF!')

def search(ls, val):
    i = 0
    while i < len(ls):
        if ls[i] == val:
            return True
        i = i + 1
    return False

def index(ls, val):
    i = 0
    while i < len(ls):
        if ls[i] == val:
            return i
        i = i + 1
    return -1

def fibonacci(n):
    import math
    Phi = 1.61803398875
    return int((Phi ** n - (1 - Phi) ** n) / math.sqrt(5))


def search(str, letter):
    if letter in str:
        return True
    else:
        return False


def index(str, letter):
    i = 0
    while i < len(str) and str[i] != letter:
        i = i + 1
    if i < len(str):
        return i
    else:
        return '-1'


def countdown(num):
    while num >= 1:
        print(num)
        time.sleep(0.1)
        num = num - 1
    print('LIFT OFF!')


def countdown(num):
    while int(num) > 0:
        print(num)
        num = num - 1
        time.sleep(0.1)
    print('LIFT OFF!')


def search(str, letter):
    if letter in str:
        print('True')


def search(str, letter):
    if letter in str:
        print('True')
    else:
        print('False')


def search(str, letter):
    if letter in str:
        return 'True'
    else:
        return 'False'


def index(str, letter):
    i = 0
    while i < len(str):
        if str[i] == letter:
            print(i)
        else:
            i += 1
    print('-1')


def countdown(num=3):
    while num != 0:
        print(num)
        num = num - 1
    print('LIFT OFF!')

def search(ls, val):
    i = 0
    while i < len(ls):
        if ls[i] == val:
            return True
        i = i + 1
    return False

def index(ls, val):
    i = 0
    while i < len(ls):
        if ls[i] == val:
            return i
        i = i + 1
    return -1

def fibonacci(n):
    a = [0, 1, 1]
    i = 3
    while i < n:
        a.append(a[i - 1] + a[i - 2])
        i = i + 1
    print(a[n])


def countdown(num=3):
    while num != 0:
        print(num)
        num = num - 1
    print('LIFT OFF!')


def search(ls, val):
    i = 0
    while i < len(ls):
        if ls[i] == val:
            return True
        i = i + 1
    return False


def countdown(num=3):
    if num != 0:
        print(num)
        countdown(num - 1)
    else:
        print('LIFT OFF!')

def search(ls, val):
    i = 0
    while i < len(ls):
        if ls[i] == val:
            return True
        i = i + 1
    return False

def index(ls, val):
    i = 0
    while i < len(ls):
        if ls[i] == val:
            return i
        i = i + 1
    return -1

def fibonacci(n):
    import math
    Phi = 1.61803398875
    return int((Phi ** n - (1 - Phi) ** n) / math.sqrt(5))


def countdown(num=3):
    while num != 0:
        print(num)
        num = num - 1
    print('LIFT OFF!')

def search(ls, val):
    i = 0
    while i < len(ls):
        if ls[i] == val:
            return True
        i = i + 1
    return False

def index(ls, val):
    i = 0
    while i < len(ls):
        if ls[i] == val:
            return i
        i = i + 1
    return -1

def fibonacci(n):
    a = [0, 1, 1]
    i = 3
    while i < n:
        a.append(a[i - 1] + a[i - 2])
        i = i + 1
    return a[n]


def countdown(num=3):
    while num != 0:
        print(num)
        num = num - 1
    print('LIFT OFF!')

def search(ls, val):
    i = 0
    while i < len(ls):
        if ls[i] == val:
            return True
        i = i + 1
    return False

def index(ls, val):
    i = 0
    while i < len(ls):
        if ls[i] == val:
            return i
        i = i + 1
    return -1

def fibonacci(n):
    a = [0, 1, 1]
    i = 3
    while i < n:
        a.append(a[i - 1] + a[i - 2])
        i = i + 1
    a.append(a[i - 1] + a[i - 2])
    return a[n]


def fibonacci(n):
    a = [0, 1, 1]
    i = 3
    while i < n:
        a.append(a[i - 1] + a[i - 2])
        i = i + 1
    a.append(a[i - 1] + a[i - 2])
    return a[n]


def index(ls, val):
    i = 0
    while i < len(ls):
        if ls[i] == val:
            return i
        i = i + 1
    return -1


def index(str, letter):
    i = 0
    while i < len(str):
        if str[i] == letter:
            return i
        i += 1
    print('-1')


def countdown(num=3):
    if num != 0:
        print(num)
        countdown(num - 1)
    else:
        print('LIFT OFF!')


def index(str, letter):
    i = 0
    while i < len(str):
        if str[i] == letter:
            return i
        i += 1
    return '-1'


def index(str, letter):
    i = 0
    while i < len(str):
        if str[i] == letter:
            return
        i += 1
    return '-1'


def countdown(num):
    while int(num) > 0:
        print(num)
        num = num - 1
        time.sleep(0.1)
    print('LIFT OFF!')


def fibonacci(n):
    if n == 1:
        return 1
    elif n == 0:
        return 0
    else:
        return fib(n - 1) + fib(n - 2)


def fibonacci(n):
    if n == 1:
        return 1
    elif n == 0:
        return 0
    else:
        return fibonacci(n - 1) + fibonacci(n - 2)


def search(str, letter):
    if letter in str:
        return 'True'
    else:
        return 'False'


def search(ls, val, pos):
    if pos == len(ls):
        return False
    elif ls[pos] == val:
        return True
    else:
        return search(ls, val, pos + 1)


def index(str, letter1, letter2):
    i = 0
    while i < len(str):
        if str[i] == letter:
            return i
        i += 1
    return '-1'


def index(str, letter1, letter2):
    i = 0
    while i < len(str):
        if str[i] == letter1:
            return i
        i += 1
    return '-1'


def index(str, letter1, letter2):
    i = 0
    while i < len(str):
        if str[i] == letter1:
            return i
        i += 1
    return '-1'
    i = 0
    while i < len(str):
        if str[i] == letter1:
            return i
        i += 1
    return '-1'


def index(str, letter1, letter2):
    i = 0
    while i < len(str):
        if str[i] == letter1:
            return i
        i += 1
    return '-1'
    i = 0
    while i < len(str):
        if str[i] == letter2:
            return i
        i += 1
    return '-1'


def countdown(num):
    i = 1
    while i < 101:
        time.sleep(0.1)
        print(101 - i)
        i = i + 1
    print('LIFT OFF!')


def countdown(num):
    if num == 1:
        print(num)
    else:
        countdown(num - 1)


def countdown(num):
    if num == 1:
        print(num)
        countdown(num - 1)
    else:
        print('LIFT OFF!')


def countdown(num):
    if num <= 100:
        print(num)
        countdown(num - 1)
    else:
        print('LIFT OFF!')


def countdown(num):
    if num <= 100 and num > 1:
        print(num)
        time.sleep(0.1)
        countdown(num - 1)
    else:
        print('LIFT OFF!')


def countdown(num):
    if num <= 100 and num > 0:
        print(num)
        time.sleep(0.1)
        countdown(num - 1)
    else:
        print('LIFT OFF!')


def countdown(num):
    if num > 0:
        print(num)
        time.sleep(0.1)
        countdown(num - 1)
    else:
        print('LIFT OFF!')


def search(str, letter):
    i = 0
    while i < len(str):
        if str[i] == letter:
            return True
        i = i + 1
    return False


def append2list(l1, l2=[]):
    for i in l1:
        l2.append(i)
    return l2

Appends elements of a list l1 at the end of the list l2. If l2 not supplied default to empty list.


def append2list(l1=[], l2=[]):
    for i in l1:
        l2.append(i)
    return l2


def search(str, letter):
    i = 0
    while i < len(str):
        if str[i] == letter:
            return True
        i = i + 1
    return False

def index(str, letter, pos):
    if pos == len(str):
        return False
    elif str[pos] == letter:
        return True
    else:
        return search(str, letter, pos)


def countdown(num):
    while num > 0:
        print(num)
        time.sleep(0.1)
        num = num - 1
        if num == 0:
            print('LIFT OFF!')


def search(str, letter):
    if letter in str:
        return 'True'
    else:
        return 'False'


def index(str, letter):
    if letter in str:
        return str.find(letter)
    else:
        return '1'


def index(str, letter):
    if letter in str:
        return str.find(letter)
    else:
        return '+1'


def index(str, letter):
    if letter in str:
        return str.find(letter)
    else:
        return '-1'


def fibonacci(n):
    if n == 0:
        return 0
    elif n == 1:
        return 1
    else:
        return fibonacci(n - 1) + fibonacci(n - 2)


def countdown(num):
    while num >= 1:
        print(num)
        time.sleep(0.1)
        num = num + 1
        if num == 0:
            print('LIFT OFF!\t')


def countdown(num):
    while num >= 1:
        print(num)
        time.sleep(0.1)
        num = num + 1
        if num == 0:
            print('LIFT OFF!')
    i = i + 1


def countdown(num):
    while num >= 1:
        print(num)
        time.sleep(0.1)
        num = num + 1
        if num == 0:
            print('LIFT OFF!')


def index(str, letter):
    if letter in str:
        return 1
    else:
        return -1


Test if two circles overlap.


def countdown(num):
    if num >= 1:
        print(num)
        time.sleep(0.1)
        num = num + 1
        if num == 0:
            print('LIFT OFF!')


def countdown(num):
    while num >= 1:
        print(num)
        time.sleep(0.1)
        num = num + 1
    i = i + 1
    if num == 0:
        print('LIFT OFF!')


def countdown(num):
    while num >= 1:
        print(num)
        time.sleep(0.1)
        num = num + 1
    if num == 0:
        print('LIFT OFF!')


def append2list(l1, l2=None):
    if l2 == None:
        l2 = []
        for i in l1:
            l2.append(i)
    return l2


def append2list(l1, l2=None):
    if l2 == None:
        l2 = []
    for i in l1:
        l2.append(i)
    return l2


def overlap(x1=0, y1=0, r1=1, x2=0, y2=0, r2=1):
    lenradii = r1 + r2
    distbtwnpoints = sqrt((x1 - x2) ** 2 + (y2 - y1) ** 2)
    return lenradii > distbtwnpoints

Test if two circles overlap.


def fibonacci(n):
    if n < 2:
        return n
    return fibonacci(n - 2) + fib(n - 1)


def fibonacci(n):
    if n > 1:
        return fibonacci(n - 2) + fiboacci(n - 1)
    return n


def search(str, letter):
    if letter in str:
        return 'True'
    else:
        return 'False'


def fibonacci(n):
    if n == 1:
        return 1
    elif n == 0:
        return 0
    else:
        return fibonacci(n - 1) + fibonacci(n - 2)


def countdown(num):
    while num >= 1:
        return num
        time.sleep(0.1)
        num = num + 1
    if num == 0:
        return 'LIFT OFF!'


def countdown(num):
    while num >= 1:
        print(num)
        i = i + 1
        time.sleep(0.1)
        num = num + 1
    if num == 0:
        print('LIFT OFF!')


def append2list(l1, l2=[]):
    if l2 == None:
        l2 = []
    for i in l1:
        l2.append(i)
    return l2


def append2list(l1, l2=None):
    if l2 is None:
        l2 = []
    for i in l1:
        l2.append(i)
    return l2


def append2list(l1, l2=[]):
    l2 = l2 + l1
    return l2


def append2list(l1, l2=[]):
    for i in l1:
        l2.append(i)
    return l2


def fibonacci(n):
    if n == 0:
        return 0
    elif n == 1:
        return 1
    elif n > 1:
        return fibonacci(n - 1) + fibonacci(n - 2)
    else:
        return -1


def index(str, letter):
    if letter in str[i]:
        return i
    else:
        return '-1'


def countdown(num):
    if num == 0:
        print('LIFT OFF!')
    else:
        print(num)
        countdown(num - 1)


def search(str):
    if letter in str:
        return 'True'
    else:
        return 'False'


def index(str):
    if letter in str[i]:
        return i
    else:
        return '-1'


def index(str, letter):
    if letter in str[i]:
        return [i]
    else:
        return '-1'


def index(str, letter, case):
    if letter in str[i]:
        return i
    else:
        return '-1'


def index(str, letter, i):
    if letter in str[i]:
        return i
    else:
        return '-1'


def index(str, letter, position):
    if letter in str[position]:
        return position
    else:
        return '-1'


def index(str, letter, i):
    if letter in str[i]:
        return i
        print(i)
    else:
        return '-1'


def search(str, letter):
    if letter in str:
        return 'True'
    else:
        return 'False'


Test if two circles overlap.


def append2list(l1, l2=None):
    if l2 == None:
        l2 = []
    for i in l1:
        l2.append(i)
    return l2


def countdown(num):
    while num != 0:
        print(num)
        num -= 1
    print('LIFT OFF!')


def overlap(x1=0, y1=0, r1=1, x2=0, y2=0, r2=1):
    lenradii = r1 + r2
    distancebtwnpoints = sqrt((x1 - x2) ** 2 + (y2 - y1) ** 2)
    return lenradii > distancebtwnpoints

Test if two circles overlap.


def append2list(l1, l2=None):
    if l2 is None:
        l2 = []
    for i in l1:
        l2.append(i)
    return l2


def append2list(l1, l2=None):
    if l2 is None:
        l2 = []
        for i in l1:
            l2.append(i)
    return l2


def append2list(l1, l2=[]):
    for i in l1:
        l2.append(i)
    return l2


def overlap(x1, y1, r1, x2, y2, r2):
    if (x2 - x1) ** 2 + (y2 - y1) ** -1 < r1 + r2:
        return True
    else:
        return False

Test if two circles overlap.


def overlap(x1=0, y1=0, r1=1, x2=0, y2=0, r2=1):
    import math
    dist = math.sqrt((x2 - x1) ** 2 + (y2 - y1) ** 2)
    if r1 + r2 >= dist:
        return True
    else:
        return False

Test if two circles overlap.


def overlap(x1=0, y1=0, r1=1, x2=0, y2=0, r2=1):
    import math
    dist = math.sqrt((x2 - x1) ** 2 + (y2 - y1) ** 2)
    if r1 + r2 > dist:
        return True
    else:
        return False

Test if two circles overlap.


def append2list(l1, l2=None):
    for i in l1:
        l2.append(i)
    return l2


def distance(x1, y1, x2, y2):
    return sqrt((x2 - x1) ** 2 + (y2 - y1) ** 2)

def overlap(x1=0, y1=0, r1=1, x2=0, y2=0, r2=1):
    dist = distance(x1, y1, x2, y2)
    return dist < r1 + r2

Test if two circles overlap.


def overlap(x1, y1, r1, x2, y2, r2):
    dist = math.sqrt((x2 - x1) ** 2 + (y2 - y1) ** 2)
    if dist < r1 + r2:
        return True
    else:
        return False

Test if two circles overlap.


def overlap(x1=0, y1=0, r1=1, x2=0, y2=0, r2=1):
    dist = math.sqrt((x2 - x1) ** 2 + (y2 - y1) ** 2)
    if dist < r1 + r2:
        return True
    else:
        return False

Test if two circles overlap.


def append2list(l1, l2=''):
    if l2 == '':
        l2 = []
    for i in l1:
        l2.append(i)
    return l2


def append2list(l1=[], l2=[]):
    for i in l1:
        l2.append(i)
    return l2


def append2list(l1, l2=None):
    if l2 is None:
        for i in l1:
            l2.append(i)
        return l2
    else:
        return l1


def append2list(l1, l2=None):
    if l2 is None:
        l2 = []
        for i in l1:
            l2.append(i)
        return l2
    else:
        return l1


def countdown(n):
    while n > 0:
        print(n)
        time.sleep(0.1)
        n = n - 1
        if n == 0:
            print('LIFT OFF!')


def search(string, letter):
    string = input()
    letter = input()
    if letter not in string:
        print('False')
    else:
        print('True')


def search(string, letter):
    if letter not in string:
        print('False')
    else:
        print('True')


def search(string, letter):
    if letter not in string:
        return 'False'
    else:
        return 'True'


def index(sting, letter):
    if letter not in string:
        print('-1')
    if letter in string:
        a = list(string)
        print(a.index(letter))


def index(string, letter):
    if letter not in string:
        print('-1')
    if letter in string:
        a = list(string)
        print(a.index(letter))


def index(string, letter):
    if letter not in string:
        return '-1'
    if letter in string:
        a = list(string)
        return a.index(letter)


def append2list(l1, l2=None):
    if l2 is None:
        l2 = []
    l2.append(l1)
    return l2


def append2list(l1, l2=None):
    if l2 is None:
        l2 = []
    for i in l1:
        l2.append(i)
    return l2


def append2list(l1, l2=None):
    if l2 == None:
        l2 = []
    for i in l1:
        l2.append(i)
    return l2


Test if two circles overlap.


def overlap(x1=0, y1=0, r1=1, x2=0, y2=0, r2=1):
    if r1 + r2 >= sqrt((x2 - x1) ** 2 + (y2 - y1) ** 2):
        return True
    else:
        return False

Test if two circles overlap.


def append2list(l1, l2=[]):
    if l2 == 0:
        l2 = []
    for i in l1:
        l2.append(i)
    return l2


def append2list(l1, l2=0):
    if l2 == 0:
        l2 = []
    for i in l1:
        l2.append(i)
    return l2


def search(str, letter):
    if letter in str:
        return 'True'
    else:
        return 'False'


def countdown(num):
    while num >= 1:
        print(num)
        time.sleep(0.1)
        num = num + 1
        print('LIFT OFF!')


def fibonacci(n):
    if n == 1:
        return 1
    elif n == 0:
        return 0
    else:
        return fibonacci(n - 1) + fibonacci(n - 2)


def index(str, letter):
    if letter in str:
        return 1
    else:
        return -1


def countdown(num):
    while num >= 1:
        print(num)
        time.sleep(0.1)
        num = num + 1
    if num == 0:
        print('LIFT OFF!')


def index(str, letter, pos):
    if str[pos] == letter:
        print('1')
    else:
        print('-1')


def countdown(num):
    if num > 0:
        print(num)
        time.sleep(0.1)
        countdown(num - 1)
    else:
        print('LIFT OFF!')


def search(str, letter):
    i = 0
    while i < len(str):
        if str[i] == letter:
            return True
        i = i + 1
    return False


def index(str, letter, pos):
    for letter in str:
        if str[pos] == letter:
            print('1')
        else:
            print('-1')


def index(str, letter):
    for letter in str:
        if letter[i] == str:
            print('1')
        else:
            print('-1')


def index(str, letter):
    i = 0
    while i < len(str):
        if letter[i] == str:
            print('1')
        else:
            print('-1')
        i = i + 1


def overlap(x1=0, y1=0, r1=1, x2=0, y2=0, r2=1):
    dis = sqrt((x2 - x1) ** 2 + (y2 - y1) ** 2)
    if dis < r1 + r2:
        return True
    return False

Test if two circles overlap.


def append2list(l1, l=[]):
    l2 = []
    for item in l1:
        l2.append(item)
    for item in l:
        l2.append(item)
    return l2


def append2list(l1, l2=None):
    if l2 is None:
        l2 = []
    for i in l1:
        l2.append(i)
    return l2


Test if two circles overlap.


def append2list(l1, l2=[]):
    for i in l1:
        l2.append(i)
    return l2


def append2list(l1, l2=[]):
    if len(l2) == 0:
        l2 = []
    for i in l1:
        l2.append(i)
    return l2


def overlap(x1=0, y1=0, r1=1, x2=0, y2=0, r2=1):
    distance = (x2 - x1) ** 2 + (y2 - y1) ** 2
    if distance < (r1 + r2) ** 2:
        return True
    else:
        return False

Test if two circles overlap.


def append2list(l1, l2=None):
    if l2 == None:
        l2 = []
    for i in l1:
        l2.append(i)
    return l2


def append2list(l1, l2=0):
    if l2 == 0:
        l2 = []
    for i in l1:
        l2.append(i)
    return l2


def overlap(x1=0, y1=0, r1=1, x2=0, y2=0, r2=1):
    run = int(x1) - int(x2)
    rise = int(y1) - int(y2)
    distance = (run ** 2 + rise ** 2) ** 0.5
    return distance < r1 + r2

Test if two circles overlap.


def countdown(num):
    import time
    num = eval(input())
    i = 0
    while i < int(num):
        print(int(num - i))
        time.sleep(0.1)
        i = i + 1
    print('LIFT OFF!')


def countdown(num):
    import time
    i = 0
    while i < int(num):
        print(int(num - i))
        time.sleep(0.1)
        i = i + 1
    print('LIFT OFF!')


def search(str, letter):
    if letter in str:
        print('True')
    else:
        print('False')


def countdown(num):
    import time
    i = 0
    while i < int(num):
        return int(num - i)
        time.sleep(0.1)
        i = i + 1
    print('LIFT OFF!')


def search(str, letter):
    if letter in str:
        return 'True'
    else:
        return 'False'


def append2list(l1, l2=None):
    try:
        if l2 == None:
            l2 = []
            for i in l1:
                l2.append(i)
            return l2
        else:
            return l1
    except ValueError:
        return l1


def append2list(l1, l2=None):
    for i in l1:
        l2.append(i)
    return l2


def append2list(l1, l2=None):
    if l2 == None:
        for i in l1:
            l2.append(i)
        return l2
    else:
        return l1


def append2list(l1, l2=None):
    if l2 == None:
        l2 = []
        for i in l1:
            l2.append(i)
        return l2
    else:
        return l1


def index(str, letter):
    i = 0
    while str[i] == letter:
        i = i + 1
    if i == len(str):
        return '-1'
    else:
        return i


def append2list(l1, l2=None):
    if l2 == None:
        l3 = []
        for i in l1:
            l3.append(i)
        return l3
    else:
        return l1


def index(str, letter):
    i = 0
    while str[i] != letter:
        i = i + 1
    if i == len(str):
        return '-1'
    else:
        return i


def index(str, letter):
    i = 0
    while str[i - 1] != letter:
        i = i + 1
    if i == len(str):
        return '-1'
    else:
        return i


def index(str, letter):
    i = 0
    while str[i] != letter:
        return i
        i = i + 1
    if i == len(str):
        return '-1'
    else:
        return i


def index(str, letter):
    return len(str)
    i = 0
    while str[i] != letter:
        i = i + 1
    if i == len(str):
        return '-1'
    else:
        return i


def index(str, letter):
    i = 0
    while str[i] != letter and i < len(str):
        i = i + 1
    if i == len(str):
        return '-1'
    else:
        return i


def index(str, letter):
    i = 0
    while str[i] != letter and i < len(str) - 1:
        i = i + 1
    if i == len(str):
        return '-1'
    else:
        return i


def overlap(x1=0, y1=0, r1=1, x2=0, y2=0, r2=1):
    if math.sqrt(x2 + y2 + (x1 + y1)) > r2 + r1:
        return True
    else:
        return False

Test if two circles overlap.


def index(str, letter):
    i = 0
    while str[i] != letter and i < len(str) - 1:
        i = i + 1
    if i + 1 == len(str):
        return '-1'
    else:
        return i


def countdown(num):
    import time
    i = 0
    while i < int(num):
        print(int(num - i))
        time.sleep(0.1)
        i = i + 1
    print('LIFT OFF!')


def overlap(x1=0, y1=0, r1=1, x2=0, y2=0, r2=1):
    if math.sqrt(x2 + y2 + (x1 + y1)) > math.sqrt(r2 + r1):
        return True
    else:
        return False

Test if two circles overlap.


def search(str, letter):
    if letter in str:
        return 'True'
    else:
        return 'False'


def overlap(x1=0, y1=0, r1=1, x2=0, y2=0, r2=1):
    if math.sqrt(x2 + y2 + (x1 + y1)) < math.sqrt(r2 + r1):
        return True
    else:
        return False

Test if two circles overlap.


def overlap(x1=0, y1=0, r1=1, x2=0, y2=0, r2=1):
    if math.sqrt(x2 + y2 + (x1 + y1)) < math.sqrt(r2 + r1) < math.sqrt(x2 -
        y2 + (x1 - y1)):
        return True
    else:
        return False

Test if two circles overlap.


def overlap(x1=0, y1=0, r1=1, x2=0, y2=0, r2=1):
    if math.sqrt(x2 - y2 + (x1 - y1)) < math.sqrt(r2 + r1) < math.sqrt(x2 +
        y2 + (x1 + y1)):
        return True
    else:
        return False

Test if two circles overlap.


def overlap(x1=0, y1=0, r1=1, x2=0, y2=0, r2=1):
    if math.sqrt(x2 + y2 + (x1 + y1)) < r2 + r1:
        return True
    else:
        return False

Test if two circles overlap.


def overlap(x1=0, y1=0, r1=1, x2=0, y2=0, r2=1):
    if math.sqrt(x2 - y2 + (x1 - y1)) < r2 + r1:
        return True
    else:
        return False

Test if two circles overlap.


def fibonacci(n):
    a = [0, 1]
    total = 0
    i = 1
    while i < n:
        total = int(a[i]) + int(a[i + 1])
        a.append(total)
        i = i + 1
    return a[n]


def overlap(x1=0, y1=0, r1=1, x2=0, y2=0, r2=1):
    if math.sqrt((x2 - y2) ** 2 + (x1 - y1) ** 2) < r2 + r1:
        return True
    else:
        return False

Test if two circles overlap.


def append2list(l1, l2=None):
    if l2 == None:
        l2 = []
    for i in l1:
        l2.append(i)
    return l2


def fibonacci(n):
    a = [0, 1]
    total = 0
    i = 0
    while i < n + 1:
        total = int(a[i]) + int(a[i + 1])
        a.append(total)
        i = i + 1
    return a[n]


def overlap(x1=0, y1=0, r1=1, x2=0, y2=0, r2=1):
    distance = math.sqrt(9)
    return distance

Test if two circles overlap.


def overlap(x1=0, y1=0, r1=1, x2=0, y2=0, r2=1):
    distance = math.sqrt((x2 - x1) ** 2 + (y2 - y1) ** 2)
    sumofrads = r1 + r2
    if distance < sumofrads:
        return True
    else:
        return False

Test if two circles overlap.


Test if two circles overlap.


def append2list(l1, l2=[]):
    for i in l1:
        l2.append(i)
    return l2


def append2list(l1, l2=None):
    if l2 is None:
        l2 = []
    for i in l1:
        l2.append(i)
    return l2


def overlap(x1=0, y1=0, r1=1, x2=0, y2=0, r2=1):
    radiuses = r1 + r2
    distance = sqrt((x2 - x1) ** 2 + (y2 - y1) ** 2)
    if distance < radiuses:
        return True
    else:
        return False

Test if two circles overlap.


def append2list(l1, l2=None):
    if l2 == None:
        l3 = []
        for i in l1:
            l3.append(i)
        return l3
    else:
        return l1


def append2list(l1, l2=None):
    if l2 is None:
        l2 = []
        for i in l1:
            l2.append(i)
        return l2
    else:
        return l1


def append2list(l1, l2=None):
    if l2 is None:
        l2 = []
        for i in l1:
            l2.append(i)
    return l2


def append2list(l1=None, l2=None):
    if l2 is None:
        l2 = []
        for i in l1:
            l2.append(i)
    return l2


_A = None

def append2list(l1=_A, l2=_A):
    if l2 is _A:
        l2 = []
        for i in l1:
            l2.append(i)
        return l2
    elif l1 is _A:
        l1 = []
        for i in l2:
            l1.append(i)
        return l1


def append2list(l1, l2=0):
    if l2 == 0:
        l2 = []
    for i in l1:
        l2.append(i)
    return l2


def overlap(x1=0, y1=0, r1=1, x2=0, y2=0, r2=1):
    run = int(x1) - int(x2)
    rise = int(y1) - int(y2)
    distance = (run ** 2 + rise ** 2) ** 0.5
    return distance < r1 + r2

Test if two circles overlap.


def append2list(l1, l2=[]):
    return l2 + l1


def append2list(l1, l2=[]):
    newlist = []
    for i in l2:
        newlist.append(i)
    for i in l1:
        newlist.append(i)
    return newlist


def append2list(l1, l2):
    for i in l1:
        l2.append(i)
    return l2


def append2list(l1, l2=None):
    if l2 is None:
        l2 = []
        l3 = l1 + l2
        return l3


def append2list(l1, l2=[]):
    if len(l2) == 2:
        l2 = []
    for i in l1:
        l2.append(i)
    return l2


def append2list(l1=[], l2=''):
    l2 = list(l2)
    for i in l1:
        l2.append(i)
    return l2


def overlap(d1=0, d2=0, d3=0, d4=0, d5=0, d6=0):
    r = d3 + d6
    r = r * r
    d = (d1 - d4) * (d1 - d4) - (d2 - d5) * (d2 - d5)
    if r == d:
        return True
    else:
        return False

Test if two circles overlap.


Test if two circles overlap.


def overlap(d1=0, d2=0, d3=0, d4=0, d5=0, d6=0):
    r = d3 + d6
    r = r * r
    d = (d1 - d4) * (d1 - d4) - (d2 - d5) * (d2 - d5)
    if r > d:
        return True
    else:
        return False

Test if two circles overlap.


def overlap(d1=0, d2=0, d3=0, d4=0, d5=0, d6=0):
    r = d3 + d6
    r = r * r
    d = (d1 - d4) * (d1 - d4) - (d2 - d5) * (d2 - d5)
    if r >= d:
        return True
    else:
        return False

Test if two circles overlap.


def append2list(l1, l2=None):
    l2 = []
    for i in l1:
        l2.append(i)
    return l2


def overlap(x1=0, y1=0, r1=1, x2=0, y2=0, r2=1):
    distance = math.floor(math.sqrt((x2 - x1) ** 2 + (y2 - y1) ** 2))
    return r1 + r2 > distance

Test if two circles overlap.


def overlap(d1=0, d2=0, d3=0, d4=0, d5=0, d6=0):
    r = d3 + d6
    d = math.sqrt((d1 - d4) ** 2) - (d2 - d5) ** 2
    if r >= d:
        return True
    else:
        return False

Test if two circles overlap.


def overlap(d1=0, d2=0, d3=0, d4=0, d5=0, d6=0):
    import math
    r = d3 + d6
    d = math.sqrt((d1 - d4) ** 2) - (d2 - d5) ** 2
    if r >= d:
        return True
    else:
        return False

Test if two circles overlap.


def overlap(x1=0, y1=0, r1=0, x2=0, y2=0, r2=1):
    d = (x2 - x1) ** 2 + (y2 - y1) * 2
    if distance < (r1 + r2) ** 2:
        return True
    else:
        return False

Test if two circles overlap.


def overlap(d1=0, d2=0, d3=0, d4=0, d5=0, d6=0):
    import math
    r = d3 + d6
    d = (d1 - d4) ** 2 - (d2 - d5) ** 2
    d = math.sqrt(d)
    if r >= d:
        return True
    else:
        return False

Test if two circles overlap.


def append2list(l1, l2=None):
    if l2 == None:
        l2 = []
    for i in l1:
        l2.append(i)
    return l2


def overlap(x1=0, y1=0, r1=1, x2=0, y2=0, r2=1):
    distance = (x2 - x1) ** 2 + (y2 - y1) ** 2
    if distance < (r1 + r2) ** 2:
        return True
    else:
        return False

Test if two circles overlap.


def overlap(d1=0, d2=0, d3=1, d4=0, d5=0, d6=1):
    import math
    r = d3 + d6
    d = (d1 - d4) ** 2 - (d2 - d5) ** 2
    d = math.sqrt(d)
    if r >= d:
        return True
    else:
        return False

Test if two circles overlap.


def overlap(x1=0, y1=0, x2=0, y2=0, r1=1, r2=1):
    distance = (x2 - x1) ** 2 + (y2 - y1) ** 2
    if distance < (r1 + r2) ** 2:
        return True
    else:
        return False

Test if two circles overlap.


def overlap(d1=0, d2=0, d3=1, d4=0, d5=0, d6=1):
    import math
    r = d3 + d6
    x = (d1 - d4) ** 2
    y = (d2 - d5) ** 2
    d = x + y
    d = math.sqrt(d)
    if r >= d:
        return True
    else:
        return False

Test if two circles overlap.


def overlap(d1=0, d2=0, d3=1, d4=0, d5=0, d6=1):
    import math
    r = d3 + d6
    x = (d1 - d4) ** 2
    y = (d2 - d5) ** 2
    d = x + y
    d = math.sqrt(d)
    if r > d:
        return True
    else:
        return False

Test if two circles overlap.


def append2list(l1, l2=None):
    if l2 is None:
        l2 = []
        l2.append(l1)
    return l2


def overlap(d1=0, d2=0, d3=1, d4=0, d5=0, d6=1):
    r = d3 + d6
    r = r ** 2
    x = (d1 - d4) ** 2
    y = (d2 - d5) ** 2
    d = x + y
    if r > d:
        return True
    else:
        return False

Test if two circles overlap.


Test if two circles overlap.


def overlap(d1=0, d2=0, d3=1, d4=0, d5=0, d6=1):
    import math
    r = d3 + d6
    d = math.sqrt((d1 - d4) ** 2 + (d2 - d5) ** 2)
    if r > d:
        return True
    else:
        return False

Test if two circles overlap.


def append2list(l1, l2=None):
    if l2 is None:
        l2 = []
        for i in l1:
            l2.append(l1)
        return l2
    else:
        return [l1, l2]


def append2list(l1, l2=0):
    if l2 is None:
        l2 = []
    for i in l1:
        l2.append(i)
    return l2


def append2list(l1, l2=[]):
    for i in l1:
        l2.append(i)
    return l2


def overlap(x1=0, y1=0, r1=1, x2=0, y2=0, r2=1):
    distance = math.floor(math.sqrt((x2 - x1) ** 2 + (y2 - y1) ** 2))
    return r1 + r2 > distance

Test if two circles overlap.


def append2list(l1, l2=None):
    if l2 is None:
        l2 = []
    for i in l1:
        l2.append(i)
    return l2


def append2list(l1, l2=0):
    if l2 == 0:
        l2 = []
    for i in l1:
        l2.append(i)
    return l2


def append2list(l1, l2=[]):
    l2 = []
    for i in l1:
        l2.append(i)
    return l2


def append2list(l1, l2=[]):
    if l2 is None:
        l2 = []
    for i in l1:
        l2.append(i)
    return l2


def append2list(l1, l2=None):
    for i in l1:
        if l2 == None:
            l2 = []
            l2.append(i)
        else:
            l2.append(i)
    return l2


def overlap(x1=0, y1=0, r1=1, x2=0, y2=0, r2=1):
    dist = (x2 - x1) ** 2 + (y2 - y1) ** 2
    if dist < (r1 + r2) ** 2:
        return True
    else:
        return False

Test if two circles overlap.


def overlap(x1=0, y1=0, r1=0, x2=0, y2=0, r2=0):
    length = (x2 - x1) ** 2 + (y2 - y1) ** 2
    if length < (r1 + r2) ** 2:
        return True
    else:
        return False

Test if two circles overlap.


def overlap(x1=0, y1=0, r1=1, x2=0, y2=0, r2=1):
    distance = (x2 - x1) ** 2 + (y2 - y1) ** 2
    if distance < (r1 + r2) ** 2:
        return True
    return False

Test if two circles overlap.


def overlap(x1=0, y1=0, r1=1, x2=0, y2=0, r2=1):
    length = (x2 - x1) ** 2 + (y2 - y1) ** 2
    if length < (r1 + r2) ** 2:
        return True
    else:
        return False

Test if two circles overlap.


def overlap(x1=0, y1=0, r1=1, x2=0, y2=0, r2=1):
    distance = (x2 - x1) ** 2 + (y2 - y1) ** 2
    if distance < (r1 + r2) ** 2:
        return True
    else:
        return False

Test if two circles overlap.


def overlap(x1=0, y1=0, r1=1, x2=0, y2=0, r2=1):
    radiuses = r1 + r2
    distance = sqrt((x2 - x1) ** 2 + (y2 - y1) ** 2)
    if distance < radiuses:
        return True
    else:
        return False

Test if two circles overlap.


Test if two circles overlap.


def index(str, letter):
    i = 0
    while i < len(str):
        index = letter.index('str')
        if str[i] == letter:
            return index
        else:
            return '-1'
        i = i + 1


def countdown(num):
    if num > 0:
        print(num)
        time.sleep(0.1)
        countdown(num - 1)
    else:
        print('LIFT OFF!')


def search(str, letter):
    i = 0
    while i < len(str):
        if str[i] == letter:
            return True
        i = i + 1
    return False


def overlap(x1=0, y1=0, r1=1, x2=0, y2=0, r2=1):
    import math
    d = (x2 - x1) ** 2 + (y2 - x1) ** 2
    if r1 + r2 >= math.sqrt(d):
        return True
    else:
        return False

Test if two circles overlap.


def overlap(x1=0, y1=0, r1=1, x2=0, y2=0, r2=1):
    import math
    d = math.sqrt((x2 - x1) ** 2 + (y2 - x1) ** 2)
    if r1 + r2 >= d:
        return True
    else:
        return False

Test if two circles overlap.


def overlap(x1=0, y1=0, r1=1, x2=0, y2=0, r2=1):
    import math
    d = math.sqrt((x2 - x1) ** 2 + (y2 - x1) ** 2)
    if r1 + r2 > d:
        return True
    else:
        return False

Test if two circles overlap.


def overlap(x1=0, y1=0, r1=1, x2=0, y2=0, r2=1):
    dis = sqrt((x2 - x1) ** 2 + (y2 - y1) ** 2)
    if dis < r1 + r2:
        return True
    return False

Test if two circles overlap.


def overlap(x1=0, y1=0, r1=1, x2=0, y2=0, r2=1):
    import math
    r = r1 + r2
    d = math.sqrt((x2 - x1) ** 2 + (y2 - x1) ** 2)
    print((r, d))
    if r > d:
        return True
    else:
        return False

Test if two circles overlap.


def append2list(l1, l2=None):
    if l2 == None:
        l2 = []
    for i in l1:
        l2.append(i)
    return l2


def overlap(x1=0, y1=0, r1=1, x2=0, y2=0, r2=1):
    import math
    r = r1 + r2
    d = (x2 - x1) ** 2 + (y2 - x1) ** 2
    d = math.sqrt(d)
    print((r, d))
    if r > d:
        return True
    else:
        return False

Test if two circles overlap.


def overlap(x1=0, y1=0, r1=1, x2=0, y2=0, r2=1):
    import math
    r = r1 + r2
    d = (x1 - x2) ** 2 + (y1 - x2) ** 2
    d = math.sqrt(d)
    print((r, d))
    if r > d:
        return True
    else:
        return False

Test if two circles overlap.


def fibonacci(n):
    a = [0, 1, 1]
    i = 3
    while i < n:
        a.append(a[i - 1] + a[i - 2])
        i = i + 1
    a.append(a[i - 1] + a[i - 2])
    return a[n]


def search(ls, val, pos):
    if pos == len(ls):
        return False
    elif ls[pos] == val:
        return True
    else:
        return search(ls, val, pos + 1)


def countdown(num=3):
    if num != 0:
        print(num)
        countdown(num - 1)
    else:
        print('LIFT OFF!')


def search(ls, val, na=0):
    pos = len(ls)
    if pos == len(ls):
        return False
    elif ls[pos] == val:
        return True
    else:
        return search(ls, val, pos + 1)


def search(ls, val, na=0):
    pos = len(ls)
    if pos == len(ls):
        return False
    elif ls[pos] == val:
        return True
    else:
        return search(ls, val, pos + 1)

def index(ls, val, pos):
    if pos == len(ls):
        return False
    elif ls[pos] == val:
        return True
    else:
        return search(ls, val, pos + 1)


def countdown(num):
    import time
    if n == 0:
        print('LIFT OFF!')
    else:
        print(num)
        print_hello(n - 1)


def countdown(num):
    import time
    if num == 0:
        print('LIFT OFF!')
    else:
        print(num)
        print_hello(n - 1)


def countdown(num):
    import time
    if num == 0:
        print('LIFT OFF!')
    else:
        print(num)
        countdown(n - 1)


def countdown(num):
    import time
    if num == 0:
        print('LIFT OFF!')
    else:
        print(num)
        countdown(num - 1)


def fibonacci(n):
    a = [0, 1]
    if len(a) == n + 1:
        print(a[n])
    else:
        total = int(a[n]) + int(a[n + 1])
        a.append(total)
        fibonacci(n + 1)


def search(str, letter):
    i = 0
    if letter == str[i]:
        return 'True'
    else:
        return 'False'


def fibonacci(n):
    a = [0, 1]
    if n == len(a):
        return a[n]
    else:
        total = int(a[n]) + int(a[n + 1])
        a.append(total)
        fibonacci(n + 1)


def fibonacci(n):
    a = [0, 1]
    if n < i:
        return a[n]
    else:
        i = 0
        total = int(a[i]) + int(a[i + 1])
        a.append(total)
        i = i + 1


def fibonacci(n):
    i = 0
    a = [0, 1]
    if n < i:
        return a[n]
    else:
        total = int(a[i]) + int(a[i + 1])
        a.append(total)
        i = i + 1


def fibonacci(n):
    i = 0
    original = n
    a = [0, 1]
    if n == 0:
        return a[original]
    else:
        total = int(a[i]) + int(a[i + 1])
        a.append(total)
        i = i + 1
        fibonacci(n - 1)


def fibonacci(n):
    i = 0
    a = [0, 1]
    if n == 0:
        return a[len(a)]
    else:
        total = int(a[i]) + int(a[i + 1])
        a.append(total)
        i = i + 1
        fibonacci(n - 1)


def fibonacci(n):
    i = 0
    a = [0, 1]
    if n == 0:
        return a[len(a) - 1]
    else:
        total = int(a[i]) + int(a[i + 1])
        a.append(total)
        i = i + 1
        fibonacci(n - 1)


def fibonacci(n):
    i = 0
    a = [0, 1]
    if n == 0:
        return a[len(a) - 2]
    else:
        total = int(a[i]) + int(a[i + 1])
        a.append(total)
        i = i + 1
        fibonacci(n - 1)


def fibonacci(n):
    i = 0
    a = [0, 1]
    if n == 0:
        return a[len(a) - 2]
    else:
        total = 0
        total = int(a[i]) + int(a[i + 1])
        a.append(total)
        i = i + 1
        fibonacci(n - 1)


def fibonacci(n):
    i = 0
    a = [0, 1]
    if n == 0:
        return a[len(a) - 2]
    else:
        total = 0
        total = int(a[i]) + int(a[i + 1])
        a.append(total)
        i = i + 1
        return n
        fibonacci(n - 1)


def search(str, letter):
    i = 0
    if letter == str[i]:
        return 'True'
    else:
        return 'False'
        i = i + 1


def fibonacci(n):
    i = 0
    a = [0, 1]
    if n == 0:
        return a[len(a)]
    else:
        total = 0
        total = int(a[i]) + int(a[i + 1])
        a.append(total)
        i = i + 1
        fibonacci(n - 1)


def search(str, letter):
    if str == []:
        return False
    elif str[0] == letter:
        return True
    else:
        return search(str[1:], letter)


def search(str, letter):
    if str == []:
        return 'False'
    elif str[0] == letter:
        return 'True'
    else:
        return search(str[1:], letter)


def search(str, letter):
    if str == []:
        return False
    elif str[0] == letter:
        return True
    else:
        search(str[1:], letter)


def countdown(num):
    import time
    if num == 0:
        print('LIFT OFF!')
    else:
        print(num)
        countdown(num - 1)


def search(str, letter):
    if len(str) == 0:
        return False
    elif str[0] == letter:
        return True
    else:
        return search(str[1:], letter)


def search(str, letter):
    if len(str) == 0:
        return False
    elif str[0] == letter:
        return True
    else:
        return search(str[1:], letter)

def index(str, letter):
    if len(str) == 0:
        return -1
    elif str[0] == letter:
        return
    else:
        return search(str[1:], letter)


def search(str, letter):
    if len(str) == 0:
        return False
    elif str[0] == letter:
        return True
    else:
        return search(str[1:], letter)

def index(str, letter):
    if len(str) == 0:
        return -1
    elif str[len(str)] == letter:
        return len(str)
    else:
        return search(str[:len(str)], letter)


def index(str, letter):
    if len(str) == 0:
        return -1
    elif str[len(str)] == letter:
        return len(str)
    else:
        return index(str[:len(str)], letter)


def index(str, letter):
    if len(str) == 0:
        return -1
    elif str[len(str)] == letter:
        return int(len(str))
    else:
        return index(str[:len(str)], letter)


def index(str, letter):
    if len(str) == 0:
        return -1
    elif str[len(str)] == letter:
        print(int(len(str)))
    else:
        return index(str[:len(str)], letter)


def fibonacci(n):
    a = [0, 1]
    total = 0
    i = 0
    while i < n + 1:
        total = int(a[i]) + int(a[i + 1])
        a.append(total)
        i = i + 1
    return a[n]


def index(str, letter):
    i = 0
    while str[i] != letter and i < len(str) - 1:
        i = i + 1
    if i + 1 == len(str):
        return '-1'
    else:
        return i


def search(str, letter):
    if letter in str:
        return 'True'
    else:
        return 'False'


def countdown(num):
    import time
    i = 0
    while i < int(num):
        print(int(num - i))
        time.sleep(0.1)
        i = i + 1
    print('LIFT OFF!')


def index(str, letter, pos):
    if len(str) == 0:
        return -1
    elif str[pos] == letter:
        print(pos)
    else:
        return index(str, letter, pos + 1)


def index(str, letter, pos):
    if len(str) == 0:
        return -1
    elif str[pos] == letter:
        return pos
    else:
        return index(str, letter, pos + 1)


def fibonacci(n):
    i = 0
    a = [0, 1]
    if n == 0:
        return a[len(a)]
    else:
        total = 0
        total = int(a[i]) + int(a[i + 1])
        a.append(total)
        i = i + 1
        fibonacci(n - 1)


def index(str, letter, pos):
    if len(str) - 1 == pos:
        return -1
    elif str[pos] == letter:
        return pos
    else:
        return index(str, letter, pos + 1)


def fibonacci(n):
    a = [0, 1]
    if n == len(a) - 1:
        return a[n]
    elif n != len(a) - 1:
        a.append(int(a[len(a) - 1] + a[len(a) - 2]))
    else:
        return fibonacci(n)


def fibonacci(n):
    if n == len(a) - 1:
        return a[n]
    elif n != len(a) - 1:
        a.append(int(a[len(a) - 1] + a[len(a) - 2]))
    else:
        return fibonacci(n)


def countdown(num):
    import time
    if num == 0:
        print('LIFT OFF!')
    else:
        print(num)
        countdown(num - 1)


def fibonacci(n):
    if n == len(a):
        return a[n]
    elif n != len(a) - 1:
        a.append(int(a[len(a) - 1] + a[len(a) - 2]))
    else:
        return fibonacci(n)


def search(str, letter):
    if len(str) == 0:
        return False
    elif str[0] == letter:
        return True
    else:
        return search(str[1:], letter)


def fibonacci(n):
    if n == len(a):
        return a[n]
    elif n != len(a):
        a.append(int(a[len(a) - 1] + a[len(a) - 2]))
    else:
        return fibonacci(n)


def fibonacci(n):
    a = [0, 1]
    if n == len(a):
        return a[n]
    elif n != len(a):
        a.append(int(a[len(a) - 1] + a[len(a) - 2]))
    else:
        return fibonacci(n)


def countdown(n):
    if n == 1:
        print('1')
    else:
        print(n - 1)
        countdown(n - 1)


def search(string, letter):
    if string == []:
        return False
    elif string[0] == letter:
        return True
    else:
        return search(string[1:], letter)


def countdown(n):
    if n == 1:
        print('LIFT OFF!')
    else:
        print(n - 1)
        countdown(n - 1)


def countdown(n):
    if n == 1:
        print('LIFT OFF!')
    else:
        print(n)
        countdown(n - 1)


def countdown(n):
    if n == 1:
        print('1')
        print('LIFT OFF!')
    else:
        print(n)
        countdown(n - 1)


def search(string, letter, pos):
    if pos == len(string):
        return False
    elif string[pos] == letter:
        return True
    else:
        return search(string, letter, pos + 1)


def search(ls, val):
    if ls == []:
        return False
    elif ls[0] == val:
        return True
    else:
        return search(ls[1:], val)


def search(ls, val):
    if ls == []:
        return False
    elif ls[0] == val:
        return True
    else:
        return search(ls[0:], val)


def search(str, letter):
    if letter in str:
        return True
    else:
        return False


def index(str, letter):
    i = 0
    while i < len(str) and str[i] != letter:
        i = i + 1
    if i < len(str):
        return i
    else:
        return '-1'


def countdown(num):
    while num >= 1:
        print(num)
        time.sleep(0.1)
        num = num - 1
    print('LIFT OFF!')


def fibonacci(n):
    a, b = 0, 1
    while b < n:
        a, b = b, a + b
        return b


def fibonacci(n):
    a, b = 0, 1
    while b < 10:
        a, b = b, a + b
        return b


def fibonacci(n):
    a = 0
    b = 1
    while b < n:
        prev_a = a
        a = b
        b = prev_a + b
    return a


def fibonacci(n):
    a = 0
    b = 1
    while b < n:
        prev_a = a
        a = b
        b = prev_a + b
    return b


def fibonacci(n):
    a = 0
    b = 1
    while b <= n:
        prev_a = a
        a = b
        b = prev_a + b
    return a


def fibonacci(n):
    a = 0
    b = 1
    while b <= n:
        prev_a = a
        a = b
        b = prev_a + b
    return b


def fibonacci(n):
    a = 1
    b = 1
    while b <= n:
        prev_a = a
        a = b
        b = prev_a + b
    return a


def fibonacci(n):
    a = 0
    b = 1
    while b > 0:
        prev_a = a
        a = b
        b = prev_a + b
        n -= 1
    return a


def fibonacci(n):
    a = 0
    b = 1
    while n > 0:
        prev_a = a
        a = b
        b = prev_a + b
        n -= 1
    return a


def countdown(num):
    if num == 1:
        print(num)
    else:
        print(num)
        time.sleep(0.1)
        countdown(num - 1)


def countdown(num):
    A = 'LIFT OFF!'
    if num == 1:
        print(num)
        time.sleep(0.1)
        print(A)
    else:
        print(num)
        time.sleep(0.1)
        print(A)
        countdown(num - 1)


def countdown(num):
    A = 'LIFT OFF!'
    if num == 1:
        print(num)
        time.sleep(0.1)
        print(A)
    else:
        print(num)
        time.sleep(0.1)
        countdown(num - 1)
        print(A)


def countdown(num):
    if num == 1:
        print(num)
        time.sleep(0.1)
        print('LIFT OFF!')
    else:
        print(num)
        time.sleep(0.1)
        countdown(num - 1)


def search(str, letter):
    if str == []:
        return False
    elif str[0] == letter:
        return True
    else:
        return search(str[1:], letter)


def search(str, letter):
    if str[-1] != a:
        return False
    elif str[0] == letter:
        return True
    else:
        return search(str[1:], letter)


def search(str, letter):
    if str[-1] != letter:
        return False
    elif str[0] == letter:
        return True
    else:
        return search(str[1:], letter)


def index(str, letter):
    if str[0] == letter:
        return 0
    else:
        return 1 + index(str[1:], letter)


def index(str, letter, pos):
    if pos == len(str):
        return -1
    elif str[pos] == letter:
        return pos
    else:
        return index(str[1:], letter, pos + 1)


def search(str, letter):
    if letter in str:
        return True
    else:
        return False


def countdown(num):
    while num >= 1:
        print(num)
        time.sleep(0.1)
        num = num - 1
    print('LIFT OFF!')


def index(str, letter):
    i = 0
    while i < len(str) and str[i] != letter:
        i = i + 1
    if i < len(str):
        return i
    else:
        return '-1'


def index(str, letter, pos):
    if pos == len(str):
        return -1
    elif str[pos] == letter:
        return 1
    else:
        return index(str[1:], letter, pos + 1)


def index(str, letter, pos):
    if pos == len(str):
        return -1
    elif str[pos] == letter:
        return 0
    else:
        return 1 + index(str[1:], letter, pos)


def index(str, letter, pos):
    if pos == len(str):
        return -1
    elif str[pos] == letter:
        return 0
    else:
        return index(str[1:], letter, pos + 1)


def index(str, letter, pos):
    if pos == len(str):
        return -1
    elif str[pos] == letter:
        return 0
    else:
        return index(str, letter, pos + 1)


def index(str, letter, pos):
    if pos == len(str):
        return -1
    elif str[pos] == letter:
        return pos
    else:
        return index(str, letter, pos + 1)


def fibonacci(n):
    if n == 1 or n == 2:
        return 1
    else:
        return fibonacci(n - 1) + fibonacci(n - 2)


def fibonacci(n):
    if n <= 1:
        return n
    else:
        return fibonacci(n - 1) + fibonacci(n - 2)


def search(str, letter):
    i = 0
    while i < len(str):
        if str[i] == letter:
            return True
        i = i + 1
    return False


def index(str, letter):
    i = 0
    while i < len(str):
        if str[i] == letter:
            return i
        i = i + 1
    return '-1'


def countdown(num):
    import time
    while num >= 1:
        print(num)
        time.sleep(0.1)
        num = num - 1
    print('LIFT OFF!')


def fibonacci(n):
    a = 0
    b = 0
    while n > 0:
        prev_a = a
        a = b
        b = prev_a + b
        n -= 1
    return a


def fibonacci(n):
    a = 0
    b = 1
    while n > 0:
        prev_a = a
        a = b
        b = prev_a + b
        n -= 1
    return a


def fibonacci(n):
    firN = 0
    secN = 1
    while n > 0:
        prev_N = firN
        firN = secN
        secN = prev_N + secN
        n -= 1
    return firN


def search(str, letter):
    if str == []:
        return False
    elif lstr[0] == letter:
        return True
    else:
        return search(str[1:], letter)


def countdown(num):
    if num == 1:
        print(num)
        time.sleep(0.1)
        print('LIFT OFF!')
    else:
        print(num)
        time.sleep(0.1)
        countdown(num - 1)


def search(str, letter):
    if str == []:
        return False
    elif str[0] == letter:
        return True
    else:
        return search(str[1:], letter)


def search(str, letter):
    if len(str) == 0:
        return False
    elif str[0] == letter:
        return True
    else:
        return search(str[1:], letter)


def countdown(num):
    import time
    if num == 1:
        print(num)
        time.sleep(0.1)
        print('LIFT OFF!')
    else:
        print(num)
        time.sleep(0.1)
        countdown(num - 1)


def search(str, letter):
    if str == '':
        return False
    elif str[0] == letter:
        return True
    else:
        return search(str[1:], letter)


def countdown(num):
    i = 0
    while i < len(num):
        print(num - i)
        time.sleep(0.1)
        i = i + 1
        print('LIFT OFF!')


def countdown(num):
    i = 0
    while i < num:
        print(num - i)
        time.sleep(0.1)
        i = i + 1
        print('LIFT OFF!')


def append2list(l1, l2=None):
    if l2 is None:
        l2 = []
    for i in l1:
        l2.append(i)
    return l2


def countdown(num):
    i = 0
    while i < num:
        print(num - i)
        time.sleep(0.1)
        i = i + 1
    print('LIFT OFF!')


Test if two circles overlap.


def search(str, letter):
    if letter in str:
        return True
    else:
        return False


def get_price(age):
    if int(age) < 16:
        return '5'
    elif int(age) > 60:
        return '7'
    else:
        return '10'


def weird_case(some_str):
    A = ' '
    a = []
    line = some_str.strip('\n').split(A)
    i = 0
    while i < len(line):
        word = line[i]
        x = 0
        while x < len(word):
            a.append(word[x])
            x = x + 1
        a.append(A)
        i = i + 1
    del a[len(a) - 1]
    x = -1
    i = 0
    while i < len(a):
        if a[i] != A:
            x = x + 1
        if x == 0 or x % 2 == 0:
            a[i] = str(a[i].upper())
        i = i + 1
    return ''.join(a)


def merge_lists(l1, l2):
    i = 0
    while i < len(l2):
        l1.append(l2[i])
        i = i + 1
    i = 0
    while i < len(l1):
        if i % 2 == 1 and i != 0:
            l1.remove(l1[i])
        i = i + 1
    return l1

Take two lists l1 and l2 and return a third list which contains every second element of l1 and l2.


def remove_zeros(a):
    b = []
    i = 0
    while i < len(a):
        if int(a[i]) == 0:
            a.remove(a[i])
            i = i - 1
        i = i + 1

Take a list of numbers and removes the zeros from it.

assert remove_zeros([])==None and remove_zeros([])==None and remove_zeros([5202, -24344, -6528])==None and remove_zeros([5202, -24344, -6528])==None


def countdown(num):
    num = input()
    i = 0
    while i < len(num):
        cd = int(num) - i
        time.sleep(0.1)
        i = i + 1


def countdown(num):
    num = eval(input())
    i = 0
    while i < len(num):
        cd = int(num) - i
        time.sleep(0.1)
        i = i + 1


def index(str, letter):
    if letter in str:
        i = 0
        while i < len(str):
            if letter == str[i]:
                return i
            i = i + 1
    else:
        return '-1'


def countdown(num):
    num = eval(input())
    i = 0
    while i < int(num):
        cd = int(num) - i
        time.sleep(0.1)
        i = i + 1


def countdown(num):
    num = eval(input())
    i = 0
    while i < int(num):
        cd = int(num) - i
        print(cd)
        time.sleep(0.1)
        i = i + 1


def countdown(num):
    import time
    num = eval(input())
    i = 0
    while i < int(num):
        cd = int(num) - i
        print(cd)
        time.sleep(0.1)
        i = i + 1


def countdown(num):
    i = 0
    while i < len(num):
        num[i] = num[i] - 1
        i = i + 1


def countdown(num):
    for i in range(5, 0, -1):
        print(i)
        print('LIFT OFF!')


def countdown(num):
    for i in range(5, 0, -1):
        print(i)


def countdown(num):
    for i in range(5, 0, -1):
        print(i)
        time.sleep(0.1)


def countdown(num):
    while num > 0:
        print(num)
        num = num - 1
        if n == 0:
            print('LIFT OFF!')


def countdown(num):
    while num > 0:
        print(num)
        num = num - 1
        if num == 0:
            print('LIFT OFF!')


def countdown(num):
    while num > 0:
        for n in num:
            print(num, time.sleep(0.1))
            num = num - 1
            if num == 0:
                print('LIFT OFF!')


def countdown(num):
    while num > 0:
        for n in num:
            print(n, time.sleep(0.1))
            num = num - 1
            if num == 0:
                print('LIFT OFF!')


def countdown(num):
    while num > 0:
        print(num, time.sleep(0.1))
        num = num - 1
        if num == 0:
            print('LIFT OFF!')


def countdown(num):
    while num > 0:
        print(num(time.sleep(0.1)))
        num = num - 1
        if num == 0:
            print('LIFT OFF!')


def countdown(num):
    while num > 0:
        print(num)
        num = num - 1
        if num == 0:
            for n in num:
                sys.stdout.write(n)
                time.sleep(1.0)
                print('LIFT OFF!')


def countdown(num):
    while num > 0:
        print(num)
        num = num - 1
        if num == 0:
            sys.stdout.write(num)
            time.sleep(1.0)
            print('LIFT OFF!')


def countdown(num):
    while num > 0:
        print(num)
        num = num - 1
        if num == 0:
            time.sleep(1.0)
            print('LIFT OFF!')


def countdown(n):
    while n > 0:
        print(n)
        time.sleep(0.1)
        n = n - 1
    print('LIFT OFF!')


def search(str, letter):
    if letter in str:
        print('True')
    else:
        print('False')


def search(str, letter):
    if letter in str:
        return 'True'
    else:
        return 'False'


def countdown(num):
    while num > 0:
        return num
        num = num - 1
        if num == 0:
            time.sleep(1.0)
            return 'LIFT OFF!'


def countdown(num):
    while num > 0:
        print(num)
        num = num - 1
        if num == 0:
            time.sleep(1.0)
            return 'LIFT OFF!'


def index(str, letter):
    pos_letter = 1
    i = 0
    while i < len(str):
        if letter in str:
            pos_letter = i + 1
            i = i + 1
            return pos_letter
    else:
        return '-1'


def search(string, letter):
    if string == []:
        return 'False'
    elif string[0] == letter:
        return 'True'
    else:
        search(string[1:], letter)


def index(string, letter):
    position = 0
    if string == []:
        return '-1'
    elif string[0] == letter:
        return position
    else:
        position += 1
        index(string[1:], letter)


def countdown(num):
    import time
    if num == 0:
        print('LIFT OFF!')
    else:
        print(num)
        time.sleep(0.1)
        countdown(num - 1)


def fibonacci(n):
    n1 = 0
    n2 = 1
    count = 0
    while count < n:
        if n == 0:
            print(n1)
        elif n == 1:
            print(n2)
        else:
            print(n1)
            print(n2)


def search(string, letter):
    if string == []:
        print('False')
    elif string[0] == letter:
        print('True')
    else:
        search(string[1:], letter)


def index(string, letter):
    position = 0
    if string == []:
        print('-1')
    elif string[0] == letter:
        print(position)
    else:
        position += 1
        index(string[1:], letter)


def search(string, letter):
    if string == []:
        return 'False'
    elif string[0] == letter:
        return 'True'
    else:
        return search(string[1:], letter)


def index(string, letter):
    position = 0
    if string == []:
        return '-1'
    elif string[0] == letter:
        return position
    else:
        position += 1
        return index(string[1:], letter)


def search(string, letter):
    if string == ' ':
        return 'False'
    elif string[0] == letter:
        return 'True'
    else:
        return search(string[1:], letter)


def index(string, letter):
    position = 0
    if string == ' ':
        return '-1'
    elif string[0] == letter:
        return position
    else:
        position += 1
        return index(string[1:], letter)


def search(string, letter):
    if string == '':
        return 'False'
    elif string[0] == letter:
        return 'True'
    else:
        return search(string[1:], letter)


def index(string, letter):
    position = 0
    if string == '':
        return '-1'
    elif string[0] == letter:
        return position
    else:
        position += 1
        return index(string[1:], letter)


def index(string, letter, position=0):
    if string == '':
        return '-1'
    elif string[0] == letter:
        return position
    else:
        position += 1
        return index(string[1:], letter)


def countdown(num):
    while num > 0:
        print(num)
        num = num - 1
        if num == 0:
            time.sleep(1.0)
            print('LIFT OFF!')


def index(str, letter):
    i = str[0]
    letter_pos = 1
    while i < len(str):
        if letter in str:
            letter_pos = i + 1
        i = i + 1
    return pos_letter


def search(str, letter):
    if letter in str:
        return 'True'
    else:
        return 'False'


def index(string, letter, position):
    if string == '':
        return '-1'
    elif string[0] == letter:
        return position
    else:
        position += 1
        return index(string[1:], letter)


def index(str, letter):
    i = str[0]
    letter_pos = 1
    while i < len(str):
        if letter in str:
            letter_pos = i + 1
        i = i + 1
    return letter_pos


def index(string, letter, position):
    if string == '':
        return '-1'
    elif string[0] == letter:
        return position
    else:
        position += 1
        return index(string[1:], letter, position)


def countdown(num):
    import time
    if num == 0:
        print('LIFT OFF!')
    else:
        print(num)
        time.sleep(0.1)
        countdown(num - 1)


def fibonacci(n):
    n1 = 0
    n2 = 1
    count = 0
    while count < n:
        if n == 0:
            print(n1)
        elif n == 1:
            print(n2)
        else:
            print(n1)
            print(n2)


def index(str, letter):
    i = str[0]
    letter_pos = 1
    while i < len(str):
        if letter in str:
            letter_pos = i + 1
        i = i + 1
        return letter_pos


def fibonacci(n):
    time = 0
    if n <= 1:
        return n
    else:
        return fibonnaci(n - 1) + fibonacci(n - 2)


def fibonacci(n):
    time = 0
    if n <= 1:
        return n
    else:
        return fibonacci(n - 1) + fibonacci(n - 2)


def fibonacci(n):
    if n <= 1:
        return n
    else:
        return fibonacci(n - 1) + fibonacci(n - 2)


def index(str, letter):
    i = str[0]
    letter_pos = 1
    while i < len(str):
        if letter in str:
            letter_pos = i + 1
        i = i + 1
    return letter_pos
    return '-1'


def index(str, letter):
    if letter not in str:
        return '-1'


def index(str, letter):
    i = str[0]
    letter_pos = 1
    while i < len(str):
        if letter in str:
            letter_pos = i + 1
        i = i + 1
    return letter_pos
    if letter not in str:
        return '-1'


def search(string, letter):
    if string == '':
        return 'False'
    elif string[0] == letter:
        return 'True'
    else:
        return search(string[1:], letter)


def index(str, letter):
    i = str[0]
    letter_pos = 1
    while i < len(str):
        if letter in str:
            letter_pos = i + 1
        i = i + 1
    return letter_pos
    print('-1')


def countdown(num):
    while num > 0:
        print(num)
        num = num - 1
        if num == 0:
            time.sleep(1.0)
            print('LIFT OFF!')


def index(str, letter):
    i = str[0]
    letter_pos = 1
    if letter in str:
        letter_pos = i + 1
        return letter_pos
    else:
        print('-1')


def search(str, letter):
    if letter in str:
        return 'True'
    else:
        return 'False'


def index(str, letter):
    i = str[0]
    letter_pos = 1
    while i < len(str):
        if letter in str:
            letter_pos = i + 1
        return letter_pos
    i = i + 1


def index(str, letter):
    i = str[0]
    letter_pos = 1
    while i < len(str):
        if letter in str:
            letter_pos = i + 1
        i = i + 1
    return letter_pos


def fibonacci(n):
    if n == 0 or n == 1:
        return 1
    else:
        return fibonacci(n - 1) + fibonacci(n - 2)


def fibonacci(n):
    if n == 0:
        return 0
    if n == 1:
        return 1
    else:
        return fibonacci(n - 1) + fibonacci(n - 2)


def index(str, letter):
    i = str[0]
    letter_pos = 1
    while i < len(str):
        if letter in str:
            letter_pos = i + 1
        else:
            return '-1'
        i = i + 1
    return letter_pos


def countdown(num):
    if nun == 0:
        print('LIFT OFF')
    else:
        print(num)
        num = num - 1
        time.sleep(0.1)
        return countdown(num)


def countdown(num):
    if nun == 0:
        print('LIFT OFF!')
    else:
        print(num)
        num = num - 1
        time.sleep(0.1)
        return countdown(num)


def countdown(num):
    if num == 0:
        print('LIFT OFF!')
    else:
        print(num)
        num = num - 1
        time.sleep(0.1)
        return countdown(num)


def index(string, letter):
    if letter in string:
        i = 0
        while i < len(string):
            if letter == string[i]:
                return i
            i = i + 1
    else:
        return '-1'


def fibonacci(n):
    fib = [0, 1]
    i = 2
    while i < n + 1:
        tmp = int(fib[i - 2]) + int(fib[i - 1])
        fib.append(tmp)
        i = i + 1
    return fib[n]


def search(string, letter):
    if letter in string:
        return 'True'
    else:
        return 'False'


def countdown(num):
    while num > 0:
        print(num)
        time.sleep(0.1)
        num = num - 1
    print('LIFT OFF!')


def countdown(num):
    import time
    i = 0
    while i < num:
        print(num - 1)
        time.sleep(0.1)
        i = i + 1
    print('LIFT OFF')


def search(ls, val):
    if val in ls:
        return True
    else:
        return False


def countdown(num):
    while num > 0:
        print(num)
        time.sleep(0.1)
        num -= 1
    print('LIFT OFF!')


def fibonacci(n):
    fib = [0, 1]
    i = 2
    while i < n + 1:
        tmp = int(fib[i - 2]) + int(fib[i - 1])
        fib.append(tmp)
        i += 1
    return fib[n]


def index(string, letter):
    if letter in string:
        i = 0
        while i < len(string):
            if letter == string[i]:
                return i
            i += 1
    else:
        return '-1'


def countdown(num):
    import time
    i = 0
    while i < int(num):
        print(int(num) - 1)
        time.sleep(0.1)
        i = i + 1
    print('LIFT OFF')


def countdown(num):
    import time
    i = 0
    while i < int(num):
        print(int(num) - i)
        time.sleep(0.1)
        i = i + 1
    print('LIFT OFF')


def index(string, letter):
    pos = -1
    i = 0
    while i < len(string):
        if string[i] == letter:
            pos = i
        i = i + 1
    return pos


def fibonacci(n):
    if n < 2:
        return n
    return fibonacci(n - 2) + fibonacci(n - 1)


def index(str, letter):
    if letter in str:
        return 1
    else:
        return -1


def countdown(num):
    while num >= 1:
        print(num)
        time.sleep(0.1)
        num = num + 1
    if num == 0:
        print('LIFT OFF!')


def search(str, letter):
    if letter in str:
        return 'True'
    else:
        return 'False'


def fibonacci(n):
    if n == 1:
        return 1
    elif n == 0:
        return 0
    else:
        return fibonacci(n - 1) + fibonacci(n - 2)


def countdown(num):
    import time
    i = 0
    while i < int(num):
        print(int(num) - i)
        time.sleep(0.1)
        i = i + 1
    print('LIFT OFF!')


def countdown(num):
    while num >= 1:
        print(num)
        time.sleep(0.1)
        num = num + 1
    if num == 0:
        print('LIFT OFF!')
    i = i + 1


def countdown(num):
    while num >= 1:
        print(num)


def countdown(num):
    while num >= 1:
        print(num)
        i = i + 1


def countdown(num):
    if num >= 1:
        print(num)


def countdown(num):
    if num >= 1:
        print(num)
        time.sleep(0.1)


def countdown(num):
    if num >= 1:
        print(num)
        time.sleep(0.1)
        num = num + 1
    if num == 0:
        print('LIFT OFF!')


def countdown(num):
    if num >= 1:
        print(num)
        time.sleep(0.1)
        num = num + 1
        print('LIFT OFF!')


def countdown(num):
    if num >= 1:
        print(num)
        time.sleep(0.1)
        num = num + 1
        if num == 0:
            print('LIFT OFF!')


def countdown(num):
    while num >= 1:
        print(num)
        time.sleep(0.1)
        num = num + 1
        if num == 0:
            print('LIFT OFF!')


def countdown(num):
    while num >= 1:
        print(num)
        time.sleep(0.1)
        num = num + 1
        if num == 0:
            print('LIFT OFF!')
        i = i + 1


def search(string, letter):
    if string == '':
        return False
    elif string[0] == letter:
        return True
    else:
        return search(string[1:], letter)


def index(string, letter, pos=0):
    if string == '':
        return '-1'
    elif string[0] == letter:
        return pos
    else:
        pos += 1
        return index(string[1:], letter, pos=pos)


def countdown(num):
    if num == 0:
        print('LIFT OFF!')
    else:
        print(num)
        num = num - 1
        time.sleep(0.1)
        return countdown(num)


def fibonacci(n):
    if n == 0:
        return 0
    elif n == 1:
        return 1
    elif n == 2:
        return 1
    else:
        return fibonacci(n - 2) + fibonacci(n - 1)


def index(str, letter):
    if letter in str:
        return 1
    else:
        return -1


def fibonacci(n):
    if n == 1:
        return 1
    elif n == 0:
        return 0
    else:
        return fibonacci(n - 1) + fibonacci(n - 2)


def countdown(num):
    while num >= 1:
        print(num)
        time.sleep(0.1)
        num = num + 1
        if num == 0:
            i = i + 1
            print('LIFT OFF!')


def search(str, letter):
    if letter in str:
        return 'True'
    else:
        return 'False'


def countdown(num):
    while num >= 0:
        print(num)
        time.sleep(0.1)
        num = num - 1
        if num == 0:
            print('LIFT OFF!')


def countdown(num):
    while num >= 1:
        print(num)
        time.sleep(0.1)
        num = num + 1
        if num == 0:
            i = 1 + 1
            print('LIFT OFF!')


def countdown(num):
    while num >= 1:
        print(num)
        time.sleep(0.1)
        num = num - 1
        if num == 0:
            print('LIFT OFF!')


def index(str, letter):
    i = 0
    while i < len(str):
        if str[i] == letter:
            return i
        i = i + 1
    return '-1'


def countdown(num):
    i = 0
    while num < 0:
        print(num - i)
    i = i + 1
    print('LIFT OFF!')


def search(ls, val):
    i = 0
    while i < len(ls):
        if ls[i] == val:
            return True
        i = i + 1
    return False


def fibonacci(n):
    if n == 0:
        return 0
    elif n == 1:
        return 1
    else:
        return fibonacci(n - 1) + fibonacci(n - 2)


def countdown(num):
    i = 0
    while int(num) < 0:
        print(num - i)
    i = i + 1
    print('LIFT OFF!')


def countdown(num):
    i = 0
    while num > 0:
        print(num - i)
    i = i + 1
    print('LIFT OFF!')


def index(str, letter):
    if letter in str:
        return str
    else:
        return -1


def index(str, letter):
    if letter in str:
        return letter
    else:
        return -1


def countdown(num):
    i = 0
    while num > 0:
        print(num - i - 1)
    i = i + 1
    print('LIFT OFF!')


def search(str, letter):
    i = 0
    while i < len(str):
        if str[i] == letter:
            return True
        i = i + 1
    return False


def countdown(num):
    if num > 0:
        print(num)
        time.sleep(0.1)
        countdown(num - 1)
    else:
        print('LIFT OFF!')


def index(str, letter):
    i = 0
    while i < len(str):
        index = letter.index('str')
        if str[i] == letter:
            return index
        else:
            return '-1'
        i = i + 1


def countdown(num):
    i = 0
    if num > 0:
        print(num - i)
    else:
        print('LIFT OFF!')
    i = i + 1


def fibonacci(num):
    l = [0]
    i = 0
    while num >= len(l):
        if len(l) > 1:
            num2 = l[i] + l[i - 1]
        else:
            num2 = l[i] + 1
        l.append(num2)
        i = i + 1
    return l[-1]


def search(str, letter):
    if letter in str:
        return 'True'
    else:
        return 'False'


def countdown(num):
    i = 0
    while i < num:
        print(num - i)
        time.sleep(0.1)
        i = i + 1
    print('LIFT OFF!')


def index(str, letter):
    i = 0
    while i < len(str):
        if letter in str[i]:
            return i
        i = i + 1
    else:
        return '-1'


def countdown(num):
    i = 0
    while i < len(num):
        if num > 0:
            print(num - i)
        else:
            print('LIFT OFF!')
        i = i + 1


def index(str, letter):
    i = 0
    while i < len(str):
        if str[i] == letter:
            return i
        i = i + 1
    return '-1'


def countdown(num):
    i = 0
    while num > 1:
        print(num)
        num += num - 1
    print('LIFT OFF!')


def fibonacci(n):
    if n == 0:
        return 0
    elif n == 1:
        return 1
    else:
        return fibonacci(n - 1) + fibonacci(n - 2)


def search(ls, val):
    i = 0
    while i < len(ls):
        if ls[i] == val:
            return True
        i = i + 1
    return False


def countdown(num):
    i = 0
    while num > 1:
        print(num)
        num -= 1
    print('LIFT OFF!')


def countdown(num):
    i = 0
    while num > 0:
        print(num)
        num -= 1
    print('LIFT OFF!')


def index(str, letter):
    i = 0
    while i < len(str):
        if letter in str[i]:
            return str[i]
        else:
            return '-1'


def fibonacci(n):
    first = 0
    second = 0
    while 0 < n:
        last = first
        first = second
        second = last + second
        n = n - 1
    return first


def fibonacci(n):
    first = 0
    second = 1
    while 0 < n:
        last = first
        first = second
        second = last + second
        n = n - 1
    return first


def search(str, letter):
    i = 0
    while i < len(str):
        if str[i] == letter:
            return True
        i = i + 1
    return False


def index(str, letter):
    i = 0
    while i < len(str):
        if str[i] == letter:
            return i
        else:
            return '-1'


def countdown(num):
    if num > 0:
        print(num)
        time.sleep(0.1)
        countdown(num - 1)
    else:
        print('LIFT OFF!')


def index(str, letter):
    if letter in str:
        return 1
    else:
        return -1


def countdown(num):
    while num >= 1:
        print(num)
        time.sleep(0.1)
        num = num - 1
        if num == 0:
            print('LIFT OFF!')


def fibonacci(n):
    if n == 1:
        return 1
    elif n == 0:
        return 0
    else:
        return fibonacci(n - 1) + fibonacci(n - 2)


def search(str, letter):
    if letter in str:
        return 'True'
    else:
        return 'False'


def index(str, letter, i):
    if i == len(str):
        return -1
    elif str[i] == letter:
        return i
    else:
        return index(str, letter, i + 1)


def countdown(num):
    if num == 0:
        print('LIFT OFF!')
    else:
        print(num)
        time.sleep(0.1)
        countdown(num - 1)


def search(ls, val):
    if ls == []:
        return False
    elif ls[0] == val:
        return True
    else:
        return search(ls[1:], val)


def fibonacci(n):
    if n == 0:
        return 0
    elif n == 1:
        return 1
    else:
        return fibonacci(n - 1) + fibonacci(n - 2)


def search(ls, val):
    if ls == '':
        return False
    elif ls[0] == val:
        return True
    else:
        return search(ls[1:], val)


def countdown(num):
    import time
    if n == 0:
        print('LIFT OFF!')
    else:
        print(num)
        time.sleep(0.1)
        countdown(num - 1)


def index(string, letter, rv):
    if string == []:
        return -1
    elif string[0] == letter:
        return rv
    else:
        rv = rv + 1
        return index(sring[1:], letter, rv)


def fibonacci(n):
    if n == 1 or n == 2:
        return 1
    return fibonacci(n - 1) + fibonacci(n - 2)


def countdown(num):
    import time
    if num == 0:
        print('LIFT OFF!')
    else:
        print(num)
        time.sleep(0.1)
        countdown(num - 1)


def index(string, letter, rv):
    if string == []:
        return -1
    elif string[0] == letter:
        return rv
    else:
        rv = rv + 1
        return index(string[1:], letter, rv)


def index(str, letter, pos):
    if str[pos] == letter:
        return str[pos]
    elif str[pos] != letter:
        return '-1'
    else:
        return index(str, letter, pos + 1)


def search(str, letter):
    i = 0
    while i < len(str):
        if str[i] == letter:
            return True
        i = i + 1
    return False


def countdown(num):
    if num > 0:
        print(num)
        time.sleep(0.1)
        countdown(num - 1)
    else:
        print('LIFT OFF!')


def fibonacci(n):
    if n == 1 or n == 2:
        return n
    return fibonacci(n - 1) + fibonacci(n - 2)


def search(ls, val):
    if ls == []:
        return 'False'
    elif ls[0] == val:
        return 'True'
    else:
        return search(ls[1:], val)


def search(ls, val):
    if ls == '':
        return 'False'
    elif ls[0] == val:
        return 'True'
    else:
        return search(ls[1:], val)


def index(string, letter, rv):
    if string == '':
        return -1
    elif string[0] == letter:
        return rv
    else:
        rv = rv + 1
        return index(string[1:], letter, rv)


def fibonacci(n):
    if n <= 1:
        return n
    else:
        return fibonacci(n - 1) + fibonacci(n - 2)


def countdown(n):
    import time
    if n == 1:
        print(n)
        time.sleep(0.1)
        print('LIFT OFF!')
    else:
        print(n)
        time.sleep(0.1)
        countdown(n - 1)


def index(string, letter):
    if letter in string:
        i = 0
        while i < len(string):
            if letter == string[i]:
                return i
            i = i + 1
    else:
        return '-1'


def search(string, letter):
    if letter in string:
        return 'True'
    if letter not in string:
        return 'False'


def fibonacci(n):
    fib = [0, 1]
    i = 2
    while i < n + 1:
        tmp = int(fib[i - 2]) + int(fib[i - 1])
        fib.append(tmp)
        i = i + 1
    return fib[n]


def countdown(num):
    while num > 0:
        print(num)
        time.sleep(0.1)
        num = num - 1
    print('LIFT OFF')


def countdown(num):
    while num > 0:
        print(num)
        time.sleep(0.1)
        num = num - 1
    print('LIFT OFF!')


def fibonacci(n):
    firN = 0
    secN = 1
    while n > 0:
        prev_N = firN
        firN = secN
        sec_N = prev_N + secN
        n -= 1
    return firN


def countdown(num):
    import time
    while num >= 1:
        print(num)
        time.sleep(0.1)
        num = num - 1
    print('LIFT OFF!')


def index(str, letter):
    i = 0
    while i < len(str):
        if str[i] == letter:
            return i
        i = i + 1
    return '-1'


def index(s, l, i=0):
    if i < len(s):
        if s[i] == l:
            contains = i
            return contains
        else:
            contains = -1
            return index(s, l, i + 1)
    else:
        return -1


def search(s, l, i=0):
    A = False
    if i < len(s):
        if s[i] == l:
            contains = True
            return contains
        else:
            contains = A
            return search(s, l, i + 1)
    else:
        return A


def countdown(t):
    if t == 0:
        return 'LIFT OFF!'
    else:
        print(t)
        return countdown(t - 1)


def fibonacci(n):
    if n == 0:
        return 0
    elif n == 1 or n == 2:
        return 1
    else:
        return fibonacci(n - 1) + fibonacci(n - 2)


def countdown(t):
    if t == 0:
        return 'LIFT OFF!'
    else:
        print(t)
        return countdown(t - 1)
    return 'LIFT OFF'


def countdown(t):
    A = 'LIFT OFF!'
    if t == 0:
        return A
        print(A)
    else:
        print(t)
        return countdown(t - 1)


def countdown(t):
    A = 'LIFT OFF!'
    if t == 0:
        print(A)
        return A
    else:
        print(t)
        return countdown(t - 1)


def fibonacci(n):
    if n <= 1:
        return n
    else:
        return fibonacci(n - 1) + fibonacci(n - 2)


def countdown(num):
    import time
    if num == 1:
        print(num)
        time.sleep(0.1)
        print('LIFT OFF!')
    else:
        print(num)
        time.sleep(0.1)
        countdown(num - 1)


def index(str, letter, pos):
    if pos == len(str):
        return -1
    elif str[pos] == letter:
        return pos
    else:
        return index(str, letter, pos + 1)


def search(str, letter):
    if str == '':
        return False
    elif str[0] == letter:
        return True
    else:
        return search(str[1:], letter)


def search(str, letter):
    i = 0
    while i < len(str):
        if str[i] == letter:
            return True
        i = i + 1
    return False


def fibonacci(n):
    values = [0, 1]
    i = 2
    while i <= n:
        terms.append(values[i - 1] + values[i - 2])
        i = i + 1
    return values[n]


def countdown(num):
    while num != 0:
        print(num)
        num -= 1
    print('LIFT OFF!')


def index(str, letter):
    if letter not in str:
        return -1
    else:
        count = 0
        while str[count] != letter:
            count += 1
    return count


def search(str, letter):
    if letter not in str:
        return 'False'
    else:
        return 'True'


def fibonacci(n):
    values = [0, 1]
    i = 2
    while i <= n:
        values.append(values[i - 1] + values[i - 2])
        i = i + 1
    return values[n]


def index(str, letter, default=0):
    while default == 0:
        if letter not in str:
            return -1
        else:
            count = 0
            while str[count] != letter:
                count += 1
    return count


def index(str, letter, default=0):
    if default == 0:
        if letter not in str:
            return -1
        else:
            count = 0
            while str[count] != letter:
                count += 1
    return count


def countdown(n):
    if n == 0:
        print('LIFT OFF!')
    else:
        print(n)
        countdown(n - 1)
    time.sleep(0.1)


def countdown(num):
    while num >= 1:
        print(num)
        time.sleep(0.1)
        num = num - 1
    if num == 0:
        print('LIFT OFF!')


def search(str, letter):
    i = 0
    while i < len(str):
        if letter in str:
            return True
        else:
            return False
        i = i + 1


def search(string, letter):
    if letter not in string:
        return 'False'
    else:
        return 'True'


def index(string, letter):
    i = 0
    a = []
    while i < len(string):
        if string == letter:
            return i
        i = i + 1
    if letter not in a:
        return '-1'


def fibonacci(n):
    list = [0]
    i = 0
    while n < len(list):
        if len(list) > 1:
            new = list[i] + list[i - 1]
        else:
            new = list[i] + 1
        list.append(new)
        i = i + 1
    return list[-1]


def countdown(x):
    print(x)
    while x != 0:
        time.sleep(0.1)
        x = x + 1
        if x != 0:
            print(x)
    time.sleep(0.1)
    print('Lift off!')


def index(str, letter):
    if letter in str:
        print(1)


def countdown(x):
    print(x)
    while x != 0:
        time.sleep(0.1)
        x = x + 1
        if x != 0:
            print(x)
    time.sleep(0.1)
    print('LIFT OFF!')


def fibonacci(n):
    list = [0]
    i = 0
    while n >= len(list):
        if len(list) > 1:
            new = list[i] + list[i - 1]
        else:
            new = list[i] + 1
        list.append(new)
        i = i + 1
    return list[-1]


def countdown(x):
    print(x)
    while x != 0:
        time.sleep(0.1)
        x = x - 1
        if x != 0:
            print(x)
    time.sleep(0.1)
    print('LIFT OFF!')


def index(string, letter):
    i = 0
    a = []
    while i < len(string):
        a.append(string[i])
        if string[i] == letter:
            return i
        i = i + 1
    if letter not in a:
        return '-1'


def countdown(num):
    import time
    if num == 1:
        print('1')
        time.sleep(0.1)
        print('LIFT OFF!')
    else:
        print(num)
        time.sleep(0.1)
        countdown(num - 1)


def fibonacci(n):
    if n == 0:
        return 0
    if n == 1:
        return 1
    else:
        return fibonacci(n - 1) + fibonacci(n - 2)


def index(str, letter):
    i = 0
    while i < len(str):
        if str[i] == letter:
            return i
        i = i + 1
    return -1


def countdown(num):
    while num > 0:
        print(num)
        num = num - 1
        if num == 0:
            time.sleep(1.0)
            print('LIFT OFF!')


def search(str, letter):
    if letter in str:
        return 'True'
    else:
        return 'False'


def search(str, letter):
    if str == '':
        return False
    elif str[0] == letter:
        return True
    else:
        return search(str[1:], letter)


def countdown(num):
    if num == 0:
        print('LIFT OFF!')
    else:
        print(num)
        countdown(num - 1)


def index(str, letter, i):
    if letter in str[i]:
        return i
    else:
        return '-1'


def fibonacci(n):
    if n == 0:
        return 0
    elif n == 1:
        return 1
    elif n > 1:
        return fibonacci(n - 1) + fibonacci(n - 2)
    else:
        return -1


def index(str, letter, i):
    if letter in str[i]:
        return i
    else:
        return '1'


def index(str, letter):
    if letter in str:
        return 1
    else:
        return -1


def fibonacci(n):
    if n == 1:
        return 1
    elif n == 0:
        return 0
    else:
        return fibonacci(n - 1) + fibonacci(n - 2)


def index(str, letter):
    pos = 0
    if pos == len(str):
        return '-1'
    elif str[pos] == letter:
        return True
    else:
        return index(str, letter, pos + 1)


def index(str, letter):
    pos = 0
    if pos == len(str):
        return '-1'
    elif str[pos] == letter:
        return pos
    else:
        return index(str, letter, pos + 1)


def fibonacci(n):
    a, b = 0, 1
    for num in range(n):
        a, b = b, a + b
        return a


def index(str, letter):
    position = 0
    if position == len(str):
        return '-1'
    elif str[position] == letter:
        return pos
    else:
        return index(str, letter, position + 1)


def index(str, letter, position):
    if position == len(str):
        return '-1'
    elif str[position] == letter:
        return pos
    else:
        return index(str, letter, position + 1)


def countdown(num):
    import time
    if num == 1:
        print('1')
        time.sleep(0.1)
        print('LIFT OFF!')
    else:
        print(num)
        time.sleep(0.1)
        countdown(num - 1)


def index(str, letter, position):
    if position == len(str):
        return '-1'
    elif str[position] == letter:
        return position
    else:
        return index(str, letter, position + 1)


def index(str, letter, i):
    if letter in str[i]:
        return i
    else:
        return -1


def countdown(num):
    if n == 0:
        print(0)
    else:
        print(num)
        countdown(n - 1)


def countdown(num):
    if num == 0:
        print(0)
    else:
        print(num)
        countdown(n - 1)


def search(str, letter):
    if letter in str:
        return 'True'
    else:
        return 'False'


def index(str, letter):
    i = 0
    while i < len(str):
        if str[i] == letter:
            return i
        i += 1
    return '-1'


def countdown(number):
    while int(number) > 0:
        print(number)
        number = number - 1
        time.sleep(0.1)
    print('LIFT OFF!')


def countdown(num):
    if num == 0:
        print(0)
    else:
        print(num)
        countdown(num - 1)


def countdown(x):
    print(x)
    while x != 0:
        time.sleep(0.1)
        x = x - 1
        if x != 0:
            print(x)
    time.sleep(0.1)
    print('LIFT OFF!')


def index(string, letter):
    i = 0
    a = []
    while i < len(string):
        a.append(string[i])


def search(string, letter):
    if letter not in string:
        return 'False'
    else:
        return 'True'


def fibonacci(n):
    if n == 1:
        return 1
    elif n == 0:
        return 0
    else:
        return fibonacci(n - 1) + fibonacci(n - 2)


def countdown(num):
    if num == 0:
        print('LIFT OFF!')
    else:
        print(num)
        countdown(num - 1)


def index(str, letter):
    if letter in str:
        return 1
    else:
        return -1


def search(string, letter):
    if string[0] == letter:
        return 'True'
    else:
        return 'False'
        return search(string[1:], letter)


def countdown(n):
    if n == 0:
        print('LIFT OFF!')
    else:
        print(n)
        countdown(n - 1)
    time.sleep(0.1)
    countdown(3)


def countdown(n):
    if n == 0:
        print('LIFT OFF!')
    else:
        print(n)
        countdown(n - 1)
    time.sleep(0.1)


def search(str, letter):
    i = 0
    while i < len(str):
        if letter in str:
            return True
        else:
            return False
        i = i + 1


def index(str, letter):
    if letter in str:
        return str.find(letter)
    else:
        return -1


def fibonacci(n):
    if n == 0:
        return 0
    else:
        return fibonacci(n - 2) + fibonacci(n - 1)


def countdown(num):
    while num >= 1:
        print(num)
        time.sleep(0.1)
        num = num - 1
    if num == 0:
        print('LIFT OFF!')


def search(str, letter):
    if letter in str:
        return 'True'
    else:
        return 'False'


def fibonacci(n):
    if n == 0:
        return 0
    elif n == 1:
        return 1
    else:
        return fibonacci(n - 2) + fibonacci(n - 1)


def fibonacci(n):
    values = [0, 1]
    i = 2
    while i <= n:
        values.append(values[i - 1] + values[i - 2])
        i = i + 1
    return values[n]


def countdown(num):
    while num != 0:
        print(num)
        num -= 1
    print('LIFT OFF!')


def search(str, letter):
    i = 0
    while i < len(str):
        if str[i] == letter:
            return 'True'
        i += 1
    return False


def index(str, letter):
    if letter not in str:
        return -1
    else:
        count = 0
        while str[count] != letter:
            count += 1
    return count


def search(string, letter):
    if string[0] == letter:
        return 'True'
    else:
        return search(string[1:], letter)
    return 'False'


def index(string, letter):
    i = 0
    a = []
    while i < len(string):
        a.append(string[i])
        if string[i] == letter:
            return i
        i = i + 1
    if letter not in a:
        return '-1'


def fibonacci(n):
    list = [0]
    i = 0
    while n >= len(list):
        if len(list) > 1:
            new = list[i] + list[i - 1]
        else:
            new = list[i] + 1
        list.append(new)
        i = i + 1
    return list[-1]


def countdown(x):
    print(x)
    while x != 0:
        time.sleep(0.1)
        x = x - 1
        if x != 0:
            print(x)
    time.sleep(0.1)
    print('LIFT OFF!')


def search(string, letter):
    if letter not in string:
        return 'False'
    else:
        return 'True'


def fibonacci(n):
    a, b = 0, 1
    for i in range(n):
        a, b = b, a + b
    return a


def index(str, letter):
    if letter in str:
        return 1
    else:
        return -1


def countdown(num):
    if num == 0:
        print('LIFT OFF!')
    else:
        print(num)
        countdown(num - 1)


def fibonacci(n):
    if n <= 1:
        return n
    elif n == 0:
        return 0
    else:
        return fibonacci(n - 1) + fibonacci(n - 2)


def fibonacci(n):
    if n == 0:
        return 0
    elif n == 1:
        return 1
    elif n > 1:
        return fibonacci(n - 1) + fibonacci(n - 2)
    else:
        return -1


def search(str, letter):
    if str == '':
        return False
    elif str[0] == letter:
        return True
    else:
        return search(str[1:], letter)


def index(str, letter, position):
    if position == len(str):
        return '-1'
    elif str[position] == letter:
        return position
    else:
        return index(str, letter, position + 1)


def countdown(num):
    import time
    if num == 1:
        print('1')
        time.sleep(0.1)
        print('LIFT OFF!')
    else:
        print(num)
        time.sleep(0.1)
        countdown(num - 1)


def index(str, letter, occurence):
    if occurence == len(str):
        return -1
    elif str[occurence] == letter:
        return occurence
    else:
        return index(str, letter, occurence + 1)


def search(str, letter):
    if letter in str:
        return 'True'
    else:
        return 'False'


def index(string, letter):
    a = []
    while i < len(string):
        a.append(string[i])
        if string[i] == letter:
            return i
    if letter not in a:
        return '-1'