import re
from dateutil import parser

def find_smallest_date(dates):
    parsed_dates = [parser.parse(date) for date in dates]
    smallest_date = min(parsed_dates)
    print(smallest_date.strftime('%d-%m-%Y'))
    return smallest_date.strftime('%d-%m-%Y')

def validate_date(date_string):
    patterns = [
        r'^\d{2}/\d{2}/\d{4}$',    # MM/DD/YYYY
        r'^\d{2}-\d{2}-\d{4}$',    # DD-MM-YYYY
        r'^\d{2}.\d{2}.\d{4}$'    # DD.MM.YYYY 
    ]

    for pattern in patterns:
        if re.match(pattern, date_string):
            return True, pattern

    return False, pattern