organized_contracts/02/02004b73ac204b76bb1b04e6c67cc1f917ead5636084e6089111d676d6d469bc/main.sol

// This contract is part of Zellic’s smart contract dataset, which is a collection of publicly available contract code gathered as of March 2023.

// SPDX-License-Identifier: MIT


// File: @openzeppelin/contracts/security/ReentrancyGuard.sol


// OpenZeppelin Contracts v4.4.1 (security/ReentrancyGuard.sol)



pragma solidity ^0.8.0;

/**

 * @dev Contract module that helps prevent reentrant calls to a function.

 *

 * Inheriting from `ReentrancyGuard` will make the {nonReentrant} modifier

 * available, which can be applied to functions to make sure there are no nested

 * (reentrant) calls to them.

 *

 * Note that because there is a single `nonReentrant` guard, functions marked as

 * `nonReentrant` may not call one another. This can be worked around by making

 * those functions `private`, and then adding `external` `nonReentrant` entry

 * points to them.

 *

 * TIP: If you would like to learn more about reentrancy and alternative ways

 * to protect against it, check out our blog post

 * https://blog.openzeppelin.com/reentrancy-after-istanbul/[Reentrancy After Istanbul].

 */
abstract contract ReentrancyGuard {
    // Booleans are more expensive than uint256 or any type that takes up a full
    // word because each write operation emits an extra SLOAD to first read the
    // slot's contents, replace the bits taken up by the boolean, and then write
    // back. This is the compiler's defense against contract upgrades and
    // pointer aliasing, and it cannot be disabled.

    // The values being non-zero value makes deployment a bit more expensive,
    // but in exchange the refund on every call to nonReentrant will be lower in
    // amount. Since refunds are capped to a percentage of the total
    // transaction's gas, it is best to keep them low in cases like this one, to
    // increase the likelihood of the full refund coming into effect.
    uint256 private constant _NOT_ENTERED = 1;
    uint256 private constant _ENTERED = 2;

    uint256 private _status;

    constructor() {
        _status = _NOT_ENTERED;
    }

    /**

     * @dev Prevents a contract from calling itself, directly or indirectly.

     * Calling a `nonReentrant` function from another `nonReentrant`

     * function is not supported. It is possible to prevent this from happening

     * by making the `nonReentrant` function external, and making it call a

     * `private` function that does the actual work.

     */
    modifier nonReentrant() {
        // On the first call to nonReentrant, _notEntered will be true
        require(_status != _ENTERED, "ReentrancyGuard: reentrant call");

        // Any calls to nonReentrant after this point will fail
        _status = _ENTERED;

        _;

        // By storing the original value once again, a refund is triggered (see
        // https://eips.ethereum.org/EIPS/eip-2200)
        _status = _NOT_ENTERED;
    }
}

// File: contracts/witch.sol




// File: @openzeppelin/contracts/utils/cryptography/MerkleProof.sol


// OpenZeppelin Contracts (last updated v4.7.0) (utils/cryptography/MerkleProof.sol)

pragma solidity ^0.8.0;

/**

 * @dev These functions deal with verification of Merkle Tree proofs.

 *

 * The proofs can be generated using the JavaScript library

 * https://github.com/miguelmota/merkletreejs[merkletreejs].

 * Note: the hashing algorithm should be keccak256 and pair sorting should be enabled.

 *

 * See `test/utils/cryptography/MerkleProof.test.js` for some examples.

 *

 * WARNING: You should avoid using leaf values that are 64 bytes long prior to

 * hashing, or use a hash function other than keccak256 for hashing leaves.

 * This is because the concatenation of a sorted pair of internal nodes in

 * the merkle tree could be reinterpreted as a leaf value.

 */
library MerkleProof {
    /**

     * @dev Returns true if a `leaf` can be proved to be a part of a Merkle tree

     * defined by `root`. For this, a `proof` must be provided, containing

     * sibling hashes on the branch from the leaf to the root of the tree. Each

     * pair of leaves and each pair of pre-images are assumed to be sorted.

     */
    function verify(
        bytes32[] memory proof,
        bytes32 root,
        bytes32 leaf
    ) internal pure returns (bool) {
        return processProof(proof, leaf) == root;
    }

    /**

     * @dev Calldata version of {verify}

     *

     * _Available since v4.7._

     */
    function verifyCalldata(
        bytes32[] calldata proof,
        bytes32 root,
        bytes32 leaf
    ) internal pure returns (bool) {
        return processProofCalldata(proof, leaf) == root;
    }

    /**

     * @dev Returns the rebuilt hash obtained by traversing a Merkle tree up

     * from `leaf` using `proof`. A `proof` is valid if and only if the rebuilt

     * hash matches the root of the tree. When processing the proof, the pairs

     * of leafs & pre-images are assumed to be sorted.

     *

     * _Available since v4.4._

     */
    function processProof(bytes32[] memory proof, bytes32 leaf) internal pure returns (bytes32) {
        bytes32 computedHash = leaf;
        for (uint256 i = 0; i < proof.length; i++) {
            computedHash = _hashPair(computedHash, proof[i]);
        }
        return computedHash;
    }

    /**

     * @dev Calldata version of {processProof}

     *

     * _Available since v4.7._

     */
    function processProofCalldata(bytes32[] calldata proof, bytes32 leaf) internal pure returns (bytes32) {
        bytes32 computedHash = leaf;
        for (uint256 i = 0; i < proof.length; i++) {
            computedHash = _hashPair(computedHash, proof[i]);
        }
        return computedHash;
    }

    /**

     * @dev Returns true if the `leaves` can be proved to be a part of a Merkle tree defined by

     * `root`, according to `proof` and `proofFlags` as described in {processMultiProof}.

     *

     * _Available since v4.7._

     */
    function multiProofVerify(
        bytes32[] memory proof,
        bool[] memory proofFlags,
        bytes32 root,
        bytes32[] memory leaves
    ) internal pure returns (bool) {
        return processMultiProof(proof, proofFlags, leaves) == root;
    }

    /**

     * @dev Calldata version of {multiProofVerify}

     *

     * _Available since v4.7._

     */
    function multiProofVerifyCalldata(
        bytes32[] calldata proof,
        bool[] calldata proofFlags,
        bytes32 root,
        bytes32[] memory leaves
    ) internal pure returns (bool) {
        return processMultiProofCalldata(proof, proofFlags, leaves) == root;
    }

    /**

     * @dev Returns the root of a tree reconstructed from `leaves` and the sibling nodes in `proof`,

     * consuming from one or the other at each step according to the instructions given by

     * `proofFlags`.

     *

     * _Available since v4.7._

     */
    function processMultiProof(
        bytes32[] memory proof,
        bool[] memory proofFlags,
        bytes32[] memory leaves
    ) internal pure returns (bytes32 merkleRoot) {
        // This function rebuild the root hash by traversing the tree up from the leaves. The root is rebuilt by
        // consuming and producing values on a queue. The queue starts with the `leaves` array, then goes onto the
        // `hashes` array. At the end of the process, the last hash in the `hashes` array should contain the root of
        // the merkle tree.
        uint256 leavesLen = leaves.length;
        uint256 totalHashes = proofFlags.length;

        // Check proof validity.
        require(leavesLen + proof.length - 1 == totalHashes, "MerkleProof: invalid multiproof");

        // The xxxPos values are "pointers" to the next value to consume in each array. All accesses are done using
        // `xxx[xxxPos++]`, which return the current value and increment the pointer, thus mimicking a queue's "pop".
        bytes32[] memory hashes = new bytes32[](totalHashes);
        uint256 leafPos = 0;
        uint256 hashPos = 0;
        uint256 proofPos = 0;
        // At each step, we compute the next hash using two values:
        // - a value from the "main queue". If not all leaves have been consumed, we get the next leaf, otherwise we
        //   get the next hash.
        // - depending on the flag, either another value for the "main queue" (merging branches) or an element from the
        //   `proof` array.
        for (uint256 i = 0; i < totalHashes; i++) {
            bytes32 a = leafPos < leavesLen ? leaves[leafPos++] : hashes[hashPos++];
            bytes32 b = proofFlags[i] ? leafPos < leavesLen ? leaves[leafPos++] : hashes[hashPos++] : proof[proofPos++];
            hashes[i] = _hashPair(a, b);
        }

        if (totalHashes > 0) {
            return hashes[totalHashes - 1];
        } else if (leavesLen > 0) {
            return leaves[0];
        } else {
            return proof[0];
        }
    }

    /**

     * @dev Calldata version of {processMultiProof}

     *

     * _Available since v4.7._

     */
    function processMultiProofCalldata(
        bytes32[] calldata proof,
        bool[] calldata proofFlags,
        bytes32[] memory leaves
    ) internal pure returns (bytes32 merkleRoot) {
        // This function rebuild the root hash by traversing the tree up from the leaves. The root is rebuilt by
        // consuming and producing values on a queue. The queue starts with the `leaves` array, then goes onto the
        // `hashes` array. At the end of the process, the last hash in the `hashes` array should contain the root of
        // the merkle tree.
        uint256 leavesLen = leaves.length;
        uint256 totalHashes = proofFlags.length;

        // Check proof validity.
        require(leavesLen + proof.length - 1 == totalHashes, "MerkleProof: invalid multiproof");

        // The xxxPos values are "pointers" to the next value to consume in each array. All accesses are done using
        // `xxx[xxxPos++]`, which return the current value and increment the pointer, thus mimicking a queue's "pop".
        bytes32[] memory hashes = new bytes32[](totalHashes);
        uint256 leafPos = 0;
        uint256 hashPos = 0;
        uint256 proofPos = 0;
        // At each step, we compute the next hash using two values:
        // - a value from the "main queue". If not all leaves have been consumed, we get the next leaf, otherwise we
        //   get the next hash.
        // - depending on the flag, either another value for the "main queue" (merging branches) or an element from the
        //   `proof` array.
        for (uint256 i = 0; i < totalHashes; i++) {
            bytes32 a = leafPos < leavesLen ? leaves[leafPos++] : hashes[hashPos++];
            bytes32 b = proofFlags[i] ? leafPos < leavesLen ? leaves[leafPos++] : hashes[hashPos++] : proof[proofPos++];
            hashes[i] = _hashPair(a, b);
        }

        if (totalHashes > 0) {
            return hashes[totalHashes - 1];
        } else if (leavesLen > 0) {
            return leaves[0];
        } else {
            return proof[0];
        }
    }

    function _hashPair(bytes32 a, bytes32 b) private pure returns (bytes32) {
        return a < b ? _efficientHash(a, b) : _efficientHash(b, a);
    }

    function _efficientHash(bytes32 a, bytes32 b) private pure returns (bytes32 value) {
        /// @solidity memory-safe-assembly
        assembly {
            mstore(0x00, a)
            mstore(0x20, b)
            value := keccak256(0x00, 0x40)
        }
    }
}

// File: contracts/witch.sol




pragma solidity ^0.8.4;

/**

 * @dev Interface of an ERC721A compliant contract.

 */
interface IERC721A {
    /**

     * The caller must own the token or be an approved operator.

     */
    error ApprovalCallerNotOwnerNorApproved();

    /**

     * The token does not exist.

     */
    error ApprovalQueryForNonexistentToken();

    /**

     * The caller cannot approve to their own address.

     */
    error ApproveToCaller();

    /**

     * The caller cannot approve to the current owner.

     */
    error ApprovalToCurrentOwner();

    /**

     * Cannot query the balance for the zero address.

     */
    error BalanceQueryForZeroAddress();

    /**

     * Cannot mint to the zero address.

     */
    error MintToZeroAddress();

    /**

     * The quantity of tokens minted must be more than zero.

     */
    error MintZeroQuantity();

    /**

     * The token does not exist.

     */
    error OwnerQueryForNonexistentToken();

    /**

     * The caller must own the token or be an approved operator.

     */
    error TransferCallerNotOwnerNorApproved();

    /**

     * The token must be owned by `from`.

     */
    error TransferFromIncorrectOwner();

    /**

     * Cannot safely transfer to a contract that does not implement the ERC721Receiver interface.

     */
    error TransferToNonERC721ReceiverImplementer();

    /**

     * Cannot transfer to the zero address.

     */
    error TransferToZeroAddress();

    /**

     * The token does not exist.

     */
    error URIQueryForNonexistentToken();

    struct TokenOwnership {
        // The address of the owner.
        address addr;
        // Keeps track of the start time of ownership with minimal overhead for tokenomics.
        uint64 startTimestamp;
        // Whether the token has been burned.
        bool burned;
    }

    /**

     * @dev Returns the total amount of tokens stored by the contract.

     *

     * Burned tokens are calculated here, use `_totalMinted()` if you want to count just minted tokens.

     */
    function totalSupply() external view returns (uint256);

    // ==============================
    //            IERC165
    // ==============================

    /**

     * @dev Returns true if this contract implements the interface defined by

     * `interfaceId`. See the corresponding

     * https://eips.ethereum.org/EIPS/eip-165#how-interfaces-are-identified[EIP section]

     * to learn more about how these ids are created.

     *

     * This function call must use less than 30 000 gas.

     */
    function supportsInterface(bytes4 interfaceId) external view returns (bool);

    // ==============================
    //            IERC721
    // ==============================

    /**

     * @dev Emitted when `tokenId` token is transferred from `from` to `to`.

     */
    event Transfer(address indexed from, address indexed to, uint256 indexed tokenId);

    /**

     * @dev Emitted when `owner` enables `approved` to manage the `tokenId` token.

     */
    event Approval(address indexed owner, address indexed approved, uint256 indexed tokenId);

    /**

     * @dev Emitted when `owner` enables or disables (`approved`) `operator` to manage all of its assets.

     */
    event ApprovalForAll(address indexed owner, address indexed operator, bool approved);

    /**

     * @dev Returns the number of tokens in ``owner``'s account.

     */
    function balanceOf(address owner) external view returns (uint256 balance);

    /**

     * @dev Returns the owner of the `tokenId` token.

     *

     * Requirements:

     *

     * - `tokenId` must exist.

     */
    function ownerOf(uint256 tokenId) external view returns (address owner);

    /**

     * @dev Safely transfers `tokenId` token from `from` to `to`.

     *

     * Requirements:

     *

     * - `from` cannot be the zero address.

     * - `to` cannot be the zero address.

     * - `tokenId` token must exist and be owned by `from`.

     * - If the caller is not `from`, it must be approved to move this token by either {approve} or {setApprovalForAll}.

     * - If `to` refers to a smart contract, it must implement {IERC721Receiver-onERC721Received}, which is called upon a safe transfer.

     *

     * Emits a {Transfer} event.

     */
    function safeTransferFrom(
        address from,
        address to,
        uint256 tokenId,
        bytes calldata data
    ) external;

    /**

     * @dev Safely transfers `tokenId` token from `from` to `to`, checking first that contract recipients

     * are aware of the ERC721 protocol to prevent tokens from being forever locked.

     *

     * Requirements:

     *

     * - `from` cannot be the zero address.

     * - `to` cannot be the zero address.

     * - `tokenId` token must exist and be owned by `from`.

     * - If the caller is not `from`, it must be have been allowed to move this token by either {approve} or {setApprovalForAll}.

     * - If `to` refers to a smart contract, it must implement {IERC721Receiver-onERC721Received}, which is called upon a safe transfer.

     *

     * Emits a {Transfer} event.

     */
    function safeTransferFrom(
        address from,
        address to,
        uint256 tokenId
    ) external;

    /**

     * @dev Transfers `tokenId` token from `from` to `to`.

     *

     * WARNING: Usage of this method is discouraged, use {safeTransferFrom} whenever possible.

     *

     * Requirements:

     *

     * - `from` cannot be the zero address.

     * - `to` cannot be the zero address.

     * - `tokenId` token must be owned by `from`.

     * - If the caller is not `from`, it must be approved to move this token by either {approve} or {setApprovalForAll}.

     *

     * Emits a {Transfer} event.

     */
    function transferFrom(
        address from,
        address to,
        uint256 tokenId
    ) external;

    /**

     * @dev Gives permission to `to` to transfer `tokenId` token to another account.

     * The approval is cleared when the token is transferred.

     *

     * Only a single account can be approved at a time, so approving the zero address clears previous approvals.

     *

     * Requirements:

     *

     * - The caller must own the token or be an approved operator.

     * - `tokenId` must exist.

     *

     * Emits an {Approval} event.

     */
    function approve(address to, uint256 tokenId) external;

    /**

     * @dev Approve or remove `operator` as an operator for the caller.

     * Operators can call {transferFrom} or {safeTransferFrom} for any token owned by the caller.

     *

     * Requirements:

     *

     * - The `operator` cannot be the caller.

     *

     * Emits an {ApprovalForAll} event.

     */
    function setApprovalForAll(address operator, bool _approved) external;

    /**

     * @dev Returns the account approved for `tokenId` token.

     *

     * Requirements:

     *

     * - `tokenId` must exist.

     */
    function getApproved(uint256 tokenId) external view returns (address operator);

    /**

     * @dev Returns if the `operator` is allowed to manage all of the assets of `owner`.

     *

     * See {setApprovalForAll}

     */
    function isApprovedForAll(address owner, address operator) external view returns (bool);

    // ==============================
    //        IERC721Metadata
    // ==============================

    /**

     * @dev Returns the token collection name.

     */
    function name() external view returns (string memory);

    /**

     * @dev Returns the token collection symbol.

     */
    function symbol() external view returns (string memory);

    /**

     * @dev Returns the Uniform Resource Identifier (URI) for `tokenId` token.

     */
    function tokenURI(uint256 tokenId) external view returns (string memory);
}

// File: https://github.com/chiru-labs/ERC721A/blob/main/contracts/ERC721A.sol


// ERC721A Contracts v3.3.0
// Creator: Chiru Labs

pragma solidity ^0.8.4;


/**

 * @dev ERC721 token receiver interface.

 */
interface ERC721A__IERC721Receiver {
    function onERC721Received(
        address operator,
        address from,
        uint256 tokenId,
        bytes calldata data
    ) external returns (bytes4);
}

/**

 * @dev Implementation of https://eips.ethereum.org/EIPS/eip-721[ERC721] Non-Fungible Token Standard, including

 * the Metadata extension. Built to optimize for lower gas during batch mints.

 *

 * Assumes serials are sequentially minted starting at _startTokenId() (defaults to 0, e.g. 0, 1, 2, 3..).

 *

 * Assumes that an owner cannot have more than 2**64 - 1 (max value of uint64) of supply.

 *

 * Assumes that the maximum token id cannot exceed 2**256 - 1 (max value of uint256).

 */
contract ERC721A is IERC721A {
    // Mask of an entry in packed address data.
    uint256 private constant BITMASK_ADDRESS_DATA_ENTRY = (1 << 64) - 1;

    // The bit position of `numberMinted` in packed address data.
    uint256 private constant BITPOS_NUMBER_MINTED = 64;

    // The bit position of `numberBurned` in packed address data.
    uint256 private constant BITPOS_NUMBER_BURNED = 128;

    // The bit position of `aux` in packed address data.
    uint256 private constant BITPOS_AUX = 192;

    // Mask of all 256 bits in packed address data except the 64 bits for `aux`.
    uint256 private constant BITMASK_AUX_COMPLEMENT = (1 << 192) - 1;

    // The bit position of `startTimestamp` in packed ownership.
    uint256 private constant BITPOS_START_TIMESTAMP = 160;

    // The bit mask of the `burned` bit in packed ownership.
    uint256 private constant BITMASK_BURNED = 1 << 224;
    
    // The bit position of the `nextInitialized` bit in packed ownership.
    uint256 private constant BITPOS_NEXT_INITIALIZED = 225;

    // The bit mask of the `nextInitialized` bit in packed ownership.
    uint256 private constant BITMASK_NEXT_INITIALIZED = 1 << 225;

    // The tokenId of the next token to be minted.
    uint256 private _currentIndex;

    // The number of tokens burned.
    uint256 private _burnCounter;

    // Token name
    string private _name;

    // Token symbol
    string private _symbol;

    // Mapping from token ID to ownership details
    // An empty struct value does not necessarily mean the token is unowned.
    // See `_packedOwnershipOf` implementation for details.
    //
    // Bits Layout:
    // - [0..159]   `addr`
    // - [160..223] `startTimestamp`
    // - [224]      `burned`
    // - [225]      `nextInitialized`
    mapping(uint256 => uint256) private _packedOwnerships;

    // Mapping owner address to address data.
    //
    // Bits Layout:
    // - [0..63]    `balance`
    // - [64..127]  `numberMinted`
    // - [128..191] `numberBurned`
    // - [192..255] `aux`
    mapping(address => uint256) private _packedAddressData;

    // Mapping from token ID to approved address.
    mapping(uint256 => address) private _tokenApprovals;

    // Mapping from owner to operator approvals
    mapping(address => mapping(address => bool)) private _operatorApprovals;

    constructor(string memory name_, string memory symbol_) {
        _name = name_;
        _symbol = symbol_;
        _currentIndex = _startTokenId();
    }

    /**

     * @dev Returns the starting token ID. 

     * To change the starting token ID, please override this function.

     */
    function _startTokenId() internal view virtual returns (uint256) {
        return 0;
    }

    /**

     * @dev Returns the next token ID to be minted.

     */
    function _nextTokenId() internal view returns (uint256) {
        return _currentIndex;
    }

    /**

     * @dev Returns the total number of tokens in existence.

     * Burned tokens will reduce the count. 

     * To get the total number of tokens minted, please see `_totalMinted`.

     */
    function totalSupply() public view override returns (uint256) {
        // Counter underflow is impossible as _burnCounter cannot be incremented
        // more than `_currentIndex - _startTokenId()` times.
        unchecked {
            return _currentIndex - _burnCounter - _startTokenId();
        }
    }

    /**

     * @dev Returns the total amount of tokens minted in the contract.

     */
    function _totalMinted() internal view returns (uint256) {
        // Counter underflow is impossible as _currentIndex does not decrement,
        // and it is initialized to `_startTokenId()`
        unchecked {
            return _currentIndex - _startTokenId();
        }
    }

    /**

     * @dev Returns the total number of tokens burned.

     */
    function _totalBurned() internal view returns (uint256) {
        return _burnCounter;
    }

    /**

     * @dev See {IERC165-supportsInterface}.

     */
    function supportsInterface(bytes4 interfaceId) public view virtual override returns (bool) {
        // The interface IDs are constants representing the first 4 bytes of the XOR of
        // all function selectors in the interface. See: https://eips.ethereum.org/EIPS/eip-165
        // e.g. `bytes4(i.functionA.selector ^ i.functionB.selector ^ ...)`
        return
            interfaceId == 0x01ffc9a7 || // ERC165 interface ID for ERC165.
            interfaceId == 0x80ac58cd || // ERC165 interface ID for ERC721.
            interfaceId == 0x5b5e139f; // ERC165 interface ID for ERC721Metadata.
    }

    /**

     * @dev See {IERC721-balanceOf}.

     */
    function balanceOf(address owner) public view override returns (uint256) {
        if (owner == address(0)) revert BalanceQueryForZeroAddress();
        return _packedAddressData[owner] & BITMASK_ADDRESS_DATA_ENTRY;
    }

    /**

     * Returns the number of tokens minted by `owner`.

     */
    function _numberMinted(address owner) internal view returns (uint256) {
        return (_packedAddressData[owner] >> BITPOS_NUMBER_MINTED) & BITMASK_ADDRESS_DATA_ENTRY;
    }

    /**

     * Returns the number of tokens burned by or on behalf of `owner`.

     */
    function _numberBurned(address owner) internal view returns (uint256) {
        return (_packedAddressData[owner] >> BITPOS_NUMBER_BURNED) & BITMASK_ADDRESS_DATA_ENTRY;
    }

    /**

     * Returns the auxillary data for `owner`. (e.g. number of whitelist mint slots used).

     */
    function _getAux(address owner) internal view returns (uint64) {
        return uint64(_packedAddressData[owner] >> BITPOS_AUX);
    }

    /**

     * Sets the auxillary data for `owner`. (e.g. number of whitelist mint slots used).

     * If there are multiple variables, please pack them into a uint64.

     */
    function _setAux(address owner, uint64 aux) internal {
        uint256 packed = _packedAddressData[owner];
        uint256 auxCasted;
        assembly { // Cast aux without masking.
            auxCasted := aux
        }
        packed = (packed & BITMASK_AUX_COMPLEMENT) | (auxCasted << BITPOS_AUX);
        _packedAddressData[owner] = packed;
    }

    /**

     * Returns the packed ownership data of `tokenId`.

     */
    function _packedOwnershipOf(uint256 tokenId) private view returns (uint256) {
        uint256 curr = tokenId;

        unchecked {
            if (_startTokenId() <= curr)
                if (curr < _currentIndex) {
                    uint256 packed = _packedOwnerships[curr];
                    // If not burned.
                    if (packed & BITMASK_BURNED == 0) {
                        // Invariant:
                        // There will always be an ownership that has an address and is not burned
                        // before an ownership that does not have an address and is not burned.
                        // Hence, curr will not underflow.
                        //
                        // We can directly compare the packed value.
                        // If the address is zero, packed is zero.
                        while (packed == 0) {
                            packed = _packedOwnerships[--curr];
                        }
                        return packed;
                    }
                }
        }
        revert OwnerQueryForNonexistentToken();
    }

    /**

     * Returns the unpacked `TokenOwnership` struct from `packed`.

     */
    function _unpackedOwnership(uint256 packed) private pure returns (TokenOwnership memory ownership) {
        ownership.addr = address(uint160(packed));
        ownership.startTimestamp = uint64(packed >> BITPOS_START_TIMESTAMP);
        ownership.burned = packed & BITMASK_BURNED != 0;
    }

    /**

     * Returns the unpacked `TokenOwnership` struct at `index`.

     */
    function _ownershipAt(uint256 index) internal view returns (TokenOwnership memory) {
        return _unpackedOwnership(_packedOwnerships[index]);
    }

    /**

     * @dev Initializes the ownership slot minted at `index` for efficiency purposes.

     */
    function _initializeOwnershipAt(uint256 index) internal {
        if (_packedOwnerships[index] == 0) {
            _packedOwnerships[index] = _packedOwnershipOf(index);
        }
    }

    /**

     * Gas spent here starts off proportional to the maximum mint batch size.

     * It gradually moves to O(1) as tokens get transferred around in the collection over time.

     */
    function _ownershipOf(uint256 tokenId) internal view returns (TokenOwnership memory) {
        return _unpackedOwnership(_packedOwnershipOf(tokenId));
    }

    /**

     * @dev See {IERC721-ownerOf}.

     */
    function ownerOf(uint256 tokenId) public view override returns (address) {
        return address(uint160(_packedOwnershipOf(tokenId)));
    }

    /**

     * @dev See {IERC721Metadata-name}.

     */
    function name() public view virtual override returns (string memory) {
        return _name;
    }

    /**

     * @dev See {IERC721Metadata-symbol}.

     */
    function symbol() public view virtual override returns (string memory) {
        return _symbol;
    }

    /**

     * @dev See {IERC721Metadata-tokenURI}.

     */
    function tokenURI(uint256 tokenId) public view virtual override returns (string memory) {
        if (!_exists(tokenId)) revert URIQueryForNonexistentToken();

        string memory baseURI = _baseURI();
        return bytes(baseURI).length != 0 ? string(abi.encodePacked(baseURI, _toString(tokenId))) : '';
    }

    /**

     * @dev Base URI for computing {tokenURI}. If set, the resulting URI for each

     * token will be the concatenation of the `baseURI` and the `tokenId`. Empty

     * by default, can be overriden in child contracts.

     */
    function _baseURI() internal view virtual returns (string memory) {
        return '';
    }

    /**

     * @dev Casts the address to uint256 without masking.

     */
    function _addressToUint256(address value) private pure returns (uint256 result) {
        assembly {
            result := value
        }
    }

    /**

     * @dev Casts the boolean to uint256 without branching.

     */
    function _boolToUint256(bool value) private pure returns (uint256 result) {
        assembly {
            result := value
        }
    }

    /**

     * @dev See {IERC721-approve}.

     */
    function approve(address to, uint256 tokenId) public override {
        address owner = address(uint160(_packedOwnershipOf(tokenId)));
        if (to == owner) revert ApprovalToCurrentOwner();

        if (_msgSenderERC721A() != owner)
            if (!isApprovedForAll(owner, _msgSenderERC721A())) {
                revert ApprovalCallerNotOwnerNorApproved();
            }

        _tokenApprovals[tokenId] = to;
        emit Approval(owner, to, tokenId);
    }

    /**

     * @dev See {IERC721-getApproved}.

     */
    function getApproved(uint256 tokenId) public view override returns (address) {
        if (!_exists(tokenId)) revert ApprovalQueryForNonexistentToken();

        return _tokenApprovals[tokenId];
    }

    /**

     * @dev See {IERC721-setApprovalForAll}.

     */
    function setApprovalForAll(address operator, bool approved) public virtual override {
        if (operator == _msgSenderERC721A()) revert ApproveToCaller();

        _operatorApprovals[_msgSenderERC721A()][operator] = approved;
        emit ApprovalForAll(_msgSenderERC721A(), operator, approved);
    }

    /**

     * @dev See {IERC721-isApprovedForAll}.

     */
    function isApprovedForAll(address owner, address operator) public view virtual override returns (bool) {
        return _operatorApprovals[owner][operator];
    }

    /**

     * @dev See {IERC721-transferFrom}.

     */
    function transferFrom(
        address from,
        address to,
        uint256 tokenId
    ) public virtual override {
        _transfer(from, to, tokenId);
    }

    /**

     * @dev See {IERC721-safeTransferFrom}.

     */
    function safeTransferFrom(
        address from,
        address to,
        uint256 tokenId
    ) public virtual override {
        safeTransferFrom(from, to, tokenId, '');
    }

    /**

     * @dev See {IERC721-safeTransferFrom}.

     */
    function safeTransferFrom(
        address from,
        address to,
        uint256 tokenId,
        bytes memory _data
    ) public virtual override {
        _transfer(from, to, tokenId);
        if (to.code.length != 0)
            if (!_checkContractOnERC721Received(from, to, tokenId, _data)) {
                revert TransferToNonERC721ReceiverImplementer();
            }
    }

    /**

     * @dev Returns whether `tokenId` exists.

     *

     * Tokens can be managed by their owner or approved accounts via {approve} or {setApprovalForAll}.

     *

     * Tokens start existing when they are minted (`_mint`),

     */
    function _exists(uint256 tokenId) internal view returns (bool) {
        return
            _startTokenId() <= tokenId &&
            tokenId < _currentIndex && // If within bounds,
            _packedOwnerships[tokenId] & BITMASK_BURNED == 0; // and not burned.
    }

    /**

     * @dev Equivalent to `_safeMint(to, quantity, '')`.

     */
    function _safeMint(address to, uint256 quantity) internal {
        _safeMint(to, quantity, '');
    }

    /**

     * @dev Safely mints `quantity` tokens and transfers them to `to`.

     *

     * Requirements:

     *

     * - If `to` refers to a smart contract, it must implement

     *   {IERC721Receiver-onERC721Received}, which is called for each safe transfer.

     * - `quantity` must be greater than 0.

     *

     * Emits a {Transfer} event.

     */
    function _safeMint(
        address to,
        uint256 quantity,
        bytes memory _data
    ) internal {
        uint256 startTokenId = _currentIndex;
        if (to == address(0)) revert MintToZeroAddress();
        if (quantity == 0) revert MintZeroQuantity();

        _beforeTokenTransfers(address(0), to, startTokenId, quantity);

        // Overflows are incredibly unrealistic.
        // balance or numberMinted overflow if current value of either + quantity > 1.8e19 (2**64) - 1
        // updatedIndex overflows if _currentIndex + quantity > 1.2e77 (2**256) - 1
        unchecked {
            // Updates:
            // - `balance += quantity`.
            // - `numberMinted += quantity`.
            //
            // We can directly add to the balance and number minted.
            _packedAddressData[to] += quantity * ((1 << BITPOS_NUMBER_MINTED) | 1);

            // Updates:
            // - `address` to the owner.
            // - `startTimestamp` to the timestamp of minting.
            // - `burned` to `false`.
            // - `nextInitialized` to `quantity == 1`.
            _packedOwnerships[startTokenId] =
                _addressToUint256(to) |
                (block.timestamp << BITPOS_START_TIMESTAMP) |
                (_boolToUint256(quantity == 1) << BITPOS_NEXT_INITIALIZED);

            uint256 updatedIndex = startTokenId;
            uint256 end = updatedIndex + quantity;

            if (to.code.length != 0) {
                do {
                    emit Transfer(address(0), to, updatedIndex);
                    if (!_checkContractOnERC721Received(address(0), to, updatedIndex++, _data)) {
                        revert TransferToNonERC721ReceiverImplementer();
                    }
                } while (updatedIndex < end);
                // Reentrancy protection
                if (_currentIndex != startTokenId) revert();
            } else {
                do {
                    emit Transfer(address(0), to, updatedIndex++);
                } while (updatedIndex < end);
            }
            _currentIndex = updatedIndex;
        }
        _afterTokenTransfers(address(0), to, startTokenId, quantity);
    }

    

    /**

     * @dev Mints `quantity` tokens and transfers them to `to`.

     *

     * Requirements:

     *

     * - `to` cannot be the zero address.

     * - `quantity` must be greater than 0.

     *

     * Emits a {Transfer} event.

     */
    function _mint(address to, uint256 quantity) internal {
        uint256 startTokenId = _currentIndex;
        if (to == address(0)) revert MintToZeroAddress();
        if (quantity == 0) revert MintZeroQuantity();

        _beforeTokenTransfers(address(0), to, startTokenId, quantity);

        // Overflows are incredibly unrealistic.
        // balance or numberMinted overflow if current value of either + quantity > 1.8e19 (2**64) - 1
        // updatedIndex overflows if _currentIndex + quantity > 1.2e77 (2**256) - 1
        unchecked {
            // Updates:
            // - `balance += quantity`.
            // - `numberMinted += quantity`.
            //
            // We can directly add to the balance and number minted.
            _packedAddressData[to] += quantity * ((1 << BITPOS_NUMBER_MINTED) | 1);

            // Updates:
            // - `address` to the owner.
            // - `startTimestamp` to the timestamp of minting.
            // - `burned` to `false`.
            // - `nextInitialized` to `quantity == 1`.
            _packedOwnerships[startTokenId] =
                _addressToUint256(to) |
                (block.timestamp << BITPOS_START_TIMESTAMP) |
                (_boolToUint256(quantity == 1) << BITPOS_NEXT_INITIALIZED);

            uint256 updatedIndex = startTokenId;
            uint256 end = updatedIndex + quantity;

            do {
                emit Transfer(address(0), to, updatedIndex++);
            } while (updatedIndex < end);

            _currentIndex = updatedIndex;
        }
        _afterTokenTransfers(address(0), to, startTokenId, quantity);
    }

    /**

     * @dev Transfers `tokenId` from `from` to `to`.

     *

     * Requirements:

     *

     * - `to` cannot be the zero address.

     * - `tokenId` token must be owned by `from`.

     *

     * Emits a {Transfer} event.

     */
    function _transfer(
        address from,
        address to,
        uint256 tokenId
    ) private {
        uint256 prevOwnershipPacked = _packedOwnershipOf(tokenId);

        if (address(uint160(prevOwnershipPacked)) != from) revert TransferFromIncorrectOwner();

        bool isApprovedOrOwner = (_msgSenderERC721A() == from ||
            isApprovedForAll(from, _msgSenderERC721A()) ||
            getApproved(tokenId) == _msgSenderERC721A());

        if (!isApprovedOrOwner) revert TransferCallerNotOwnerNorApproved();
        if (to == address(0)) revert TransferToZeroAddress();

        _beforeTokenTransfers(from, to, tokenId, 1);

        // Clear approvals from the previous owner.
        delete _tokenApprovals[tokenId];

        // Underflow of the sender's balance is impossible because we check for
        // ownership above and the recipient's balance can't realistically overflow.
        // Counter overflow is incredibly unrealistic as tokenId would have to be 2**256.
        unchecked {
            // We can directly increment and decrement the balances.
            --_packedAddressData[from]; // Updates: `balance -= 1`.
            ++_packedAddressData[to]; // Updates: `balance += 1`.

            // Updates:
            // - `address` to the next owner.
            // - `startTimestamp` to the timestamp of transfering.
            // - `burned` to `false`.
            // - `nextInitialized` to `true`.
            _packedOwnerships[tokenId] =
                _addressToUint256(to) |
                (block.timestamp << BITPOS_START_TIMESTAMP) |
                BITMASK_NEXT_INITIALIZED;

            // If the next slot may not have been initialized (i.e. `nextInitialized == false`) .
            if (prevOwnershipPacked & BITMASK_NEXT_INITIALIZED == 0) {
                uint256 nextTokenId = tokenId + 1;
                // If the next slot's address is zero and not burned (i.e. packed value is zero).
                if (_packedOwnerships[nextTokenId] == 0) {
                    // If the next slot is within bounds.
                    if (nextTokenId != _currentIndex) {
                        // Initialize the next slot to maintain correctness for `ownerOf(tokenId + 1)`.
                        _packedOwnerships[nextTokenId] = prevOwnershipPacked;
                    }
                }
            }
        }

        emit Transfer(from, to, tokenId);
        _afterTokenTransfers(from, to, tokenId, 1);
    }

    /**

     * @dev Equivalent to `_burn(tokenId, false)`.

     */
    function _burn(uint256 tokenId) internal virtual {
        _burn(tokenId, false);
    }

    /**

     * @dev Destroys `tokenId`.

     * The approval is cleared when the token is burned.

     *

     * Requirements:

     *

     * - `tokenId` must exist.

     *

     * Emits a {Transfer} event.

     */
    function _burn(uint256 tokenId, bool approvalCheck) internal virtual {
        uint256 prevOwnershipPacked = _packedOwnershipOf(tokenId);

        address from = address(uint160(prevOwnershipPacked));

        if (approvalCheck) {
            bool isApprovedOrOwner = (_msgSenderERC721A() == from ||
                isApprovedForAll(from, _msgSenderERC721A()) ||
                getApproved(tokenId) == _msgSenderERC721A());

            if (!isApprovedOrOwner) revert TransferCallerNotOwnerNorApproved();
        }

        _beforeTokenTransfers(from, address(0), tokenId, 1);

        // Clear approvals from the previous owner.
        delete _tokenApprovals[tokenId];

        // Underflow of the sender's balance is impossible because we check for
        // ownership above and the recipient's balance can't realistically overflow.
        // Counter overflow is incredibly unrealistic as tokenId would have to be 2**256.
        unchecked {
            // Updates:
            // - `balance -= 1`.
            // - `numberBurned += 1`.
            //
            // We can directly decrement the balance, and increment the number burned.
            // This is equivalent to `packed -= 1; packed += 1 << BITPOS_NUMBER_BURNED;`.
            _packedAddressData[from] += (1 << BITPOS_NUMBER_BURNED) - 1;

            // Updates:
            // - `address` to the last owner.
            // - `startTimestamp` to the timestamp of burning.
            // - `burned` to `true`.
            // - `nextInitialized` to `true`.
            _packedOwnerships[tokenId] =
                _addressToUint256(from) |
                (block.timestamp << BITPOS_START_TIMESTAMP) |
                BITMASK_BURNED | 
                BITMASK_NEXT_INITIALIZED;

            // If the next slot may not have been initialized (i.e. `nextInitialized == false`) .
            if (prevOwnershipPacked & BITMASK_NEXT_INITIALIZED == 0) {
                uint256 nextTokenId = tokenId + 1;
                // If the next slot's address is zero and not burned (i.e. packed value is zero).
                if (_packedOwnerships[nextTokenId] == 0) {
                    // If the next slot is within bounds.
                    if (nextTokenId != _currentIndex) {
                        // Initialize the next slot to maintain correctness for `ownerOf(tokenId + 1)`.
                        _packedOwnerships[nextTokenId] = prevOwnershipPacked;
                    }
                }
            }
        }

        emit Transfer(from, address(0), tokenId);
        _afterTokenTransfers(from, address(0), tokenId, 1);

        // Overflow not possible, as _burnCounter cannot be exceed _currentIndex times.
        unchecked {
            _burnCounter++;
        }
    }

    /**

     * @dev Internal function to invoke {IERC721Receiver-onERC721Received} on a target contract.

     *

     * @param from address representing the previous owner of the given token ID

     * @param to target address that will receive the tokens

     * @param tokenId uint256 ID of the token to be transferred

     * @param _data bytes optional data to send along with the call

     * @return bool whether the call correctly returned the expected magic value

     */
    function _checkContractOnERC721Received(
        address from,
        address to,
        uint256 tokenId,
        bytes memory _data
    ) private returns (bool) {
        try ERC721A__IERC721Receiver(to).onERC721Received(_msgSenderERC721A(), from, tokenId, _data) returns (
            bytes4 retval
        ) {
            return retval == ERC721A__IERC721Receiver(to).onERC721Received.selector;
        } catch (bytes memory reason) {
            if (reason.length == 0) {
                revert TransferToNonERC721ReceiverImplementer();
            } else {
                assembly {
                    revert(add(32, reason), mload(reason))
                }
            }
        }
    }

    /**

     * @dev Hook that is called before a set of serially-ordered token ids are about to be transferred. This includes minting.

     * And also called before burning one token.

     *

     * startTokenId - the first token id to be transferred

     * quantity - the amount to be transferred

     *

     * Calling conditions:

     *

     * - When `from` and `to` are both non-zero, `from`'s `tokenId` will be

     * transferred to `to`.

     * - When `from` is zero, `tokenId` will be minted for `to`.

     * - When `to` is zero, `tokenId` will be burned by `from`.

     * - `from` and `to` are never both zero.

     */
    function _beforeTokenTransfers(
        address from,
        address to,
        uint256 startTokenId,
        uint256 quantity
    ) internal virtual {}

    /**

     * @dev Hook that is called after a set of serially-ordered token ids have been transferred. This includes

     * minting.

     * And also called after one token has been burned.

     *

     * startTokenId - the first token id to be transferred

     * quantity - the amount to be transferred

     *

     * Calling conditions:

     *

     * - When `from` and `to` are both non-zero, `from`'s `tokenId` has been

     * transferred to `to`.

     * - When `from` is zero, `tokenId` has been minted for `to`.

     * - When `to` is zero, `tokenId` has been burned by `from`.

     * - `from` and `to` are never both zero.

     */
    function _afterTokenTransfers(
        address from,
        address to,
        uint256 startTokenId,
        uint256 quantity
    ) internal virtual {}

    /**

     * @dev Returns the message sender (defaults to `msg.sender`).

     *

     * If you are writing GSN compatible contracts, you need to override this function.

     */
    function _msgSenderERC721A() internal view virtual returns (address) {
        return msg.sender;
    }

    /**

     * @dev Converts a `uint256` to its ASCII `string` decimal representation.

     */
    function _toString(uint256 value) internal pure returns (string memory ptr) {
        assembly {
            // The maximum value of a uint256 contains 78 digits (1 byte per digit), 
            // but we allocate 128 bytes to keep the free memory pointer 32-byte word aliged.
            // We will need 1 32-byte word to store the length, 
            // and 3 32-byte words to store a maximum of 78 digits. Total: 32 + 3 * 32 = 128.
            ptr := add(mload(0x40), 128)
            // Update the free memory pointer to allocate.
            mstore(0x40, ptr)

            // Cache the end of the memory to calculate the length later.
            let end := ptr

            // We write the string from the rightmost digit to the leftmost digit.
            // The following is essentially a do-while loop that also handles the zero case.
            // Costs a bit more than early returning for the zero case,
            // but cheaper in terms of deployment and overall runtime costs.
            for { 
                // Initialize and perform the first pass without check.
                let temp := value
                // Move the pointer 1 byte leftwards to point to an empty character slot.
                ptr := sub(ptr, 1)
                // Write the character to the pointer. 48 is the ASCII index of '0'.
                mstore8(ptr, add(48, mod(temp, 10)))
                temp := div(temp, 10)
            } temp { 
                // Keep dividing `temp` until zero.
                temp := div(temp, 10)
            } { // Body of the for loop.
                ptr := sub(ptr, 1)
                mstore8(ptr, add(48, mod(temp, 10)))
            }
            
            let length := sub(end, ptr)
            // Move the pointer 32 bytes leftwards to make room for the length.
            ptr := sub(ptr, 32)
            // Store the length.
            mstore(ptr, length)
        }
    }
}

// File: https://github.com/OpenZeppelin/openzeppelin-contracts/blob/master/contracts/utils/Strings.sol


// OpenZeppelin Contracts v4.4.1 (utils/Strings.sol)

pragma solidity ^0.8.0;

/**

 * @dev String operations.

 */
library Strings {
    bytes16 private constant _HEX_SYMBOLS = "0123456789abcdef";
    uint8 private constant _ADDRESS_LENGTH = 20;

    /**

     * @dev Converts a `uint256` to its ASCII `string` decimal representation.

     */
    function toString(uint256 value) internal pure returns (string memory) {
        // Inspired by OraclizeAPI's implementation - MIT licence
        // https://github.com/oraclize/ethereum-api/blob/b42146b063c7d6ee1358846c198246239e9360e8/oraclizeAPI_0.4.25.sol

        if (value == 0) {
            return "0";
        }
        uint256 temp = value;
        uint256 digits;
        while (temp != 0) {
            digits++;
            temp /= 10;
        }
        bytes memory buffer = new bytes(digits);
        while (value != 0) {
            digits -= 1;
            buffer[digits] = bytes1(uint8(48 + uint256(value % 10)));
            value /= 10;
        }
        return string(buffer);
    }

    /**

     * @dev Converts a `uint256` to its ASCII `string` hexadecimal representation.

     */
    function toHexString(uint256 value) internal pure returns (string memory) {
        if (value == 0) {
            return "0x00";
        }
        uint256 temp = value;
        uint256 length = 0;
        while (temp != 0) {
            length++;
            temp >>= 8;
        }
        return toHexString(value, length);
    }

    /**

     * @dev Converts a `uint256` to its ASCII `string` hexadecimal representation with fixed length.

     */
    function toHexString(uint256 value, uint256 length) internal pure returns (string memory) {
        bytes memory buffer = new bytes(2 * length + 2);
        buffer[0] = "0";
        buffer[1] = "x";
        for (uint256 i = 2 * length + 1; i > 1; --i) {
            buffer[i] = _HEX_SYMBOLS[value & 0xf];
            value >>= 4;
        }
        require(value == 0, "Strings: hex length insufficient");
        return string(buffer);
    }

    /**

     * @dev Converts an `address` with fixed length of 20 bytes to its not checksummed ASCII `string` hexadecimal representation.

     */
    function toHexString(address addr) internal pure returns (string memory) {
        return toHexString(uint256(uint160(addr)), _ADDRESS_LENGTH);
    }
}

// File: https://github.com/OpenZeppelin/openzeppelin-contracts/blob/master/contracts/utils/Context.sol


// OpenZeppelin Contracts v4.4.1 (utils/Context.sol)

pragma solidity ^0.8.0;

/**

 * @dev Provides information about the current execution context, including the

 * sender of the transaction and its data. While these are generally available

 * via msg.sender and msg.data, they should not be accessed in such a direct

 * manner, since when dealing with meta-transactions the account sending and

 * paying for execution may not be the actual sender (as far as an application

 * is concerned).

 *

 * This contract is only required for intermediate, library-like contracts.

 */
abstract contract Context {
    function _msgSender() internal view virtual returns (address) {
        return msg.sender;
    }

    function _msgData() internal view virtual returns (bytes calldata) {
        return msg.data;
    }
}

// File: https://github.com/OpenZeppelin/openzeppelin-contracts/blob/master/contracts/access/Ownable.sol


// OpenZeppelin Contracts v4.4.1 (access/Ownable.sol)

pragma solidity ^0.8.0;


/**

 * @dev Contract module which provides a basic access control mechanism, where

 * there is an account (an owner) that can be granted exclusive access to

 * specific functions.

 *

 * By default, the owner account will be the one that deploys the contract. This

 * can later be changed with {transferOwnership}.

 *

 * This module is used through inheritance. It will make available the modifier

 * `onlyOwner`, which can be applied to your functions to restrict their use to

 * the owner.

 */
abstract contract Ownable is Context {
    address private _owner;

    event OwnershipTransferred(address indexed previousOwner, address indexed newOwner);

    /**

     * @dev Initializes the contract setting the deployer as the initial owner.

     */
    constructor() {
        _transferOwnership(_msgSender());
    }

    /**

     * @dev Returns the address of the current owner.

     */
    function owner() public view virtual returns (address) {
        return _owner;
    }

    /**

     * @dev Throws if called by any account other than the owner.

     */
    modifier onlyOwner() {
        require(owner() == _msgSender(), "Ownable: caller is not the owner");
        _;
    }

    /**

     * @dev Leaves the contract without owner. It will not be possible to call

     * `onlyOwner` functions anymore. Can only be called by the current owner.

     *

     * NOTE: Renouncing ownership will leave the contract without an owner,

     * thereby removing any functionality that is only available to the owner.

     */
    function renounceOwnership() public virtual onlyOwner {
        _transferOwnership(address(0));
    }

    /**

     * @dev Transfers ownership of the contract to a new account (`newOwner`).

     * Can only be called by the current owner.

     */
    function transferOwnership(address newOwner) public virtual onlyOwner {
        require(newOwner != address(0), "Ownable: new owner is the zero address");
        _transferOwnership(newOwner);
    }

    /**

     * @dev Transfers ownership of the contract to a new account (`newOwner`).

     * Internal function without access restriction.

     */
    function _transferOwnership(address newOwner) internal virtual {
        address oldOwner = _owner;
        _owner = newOwner;
        emit OwnershipTransferred(oldOwner, newOwner);
    }
}

// File: https://github.com/OpenZeppelin/openzeppelin-contracts/blob/master/contracts/utils/Address.sol


// OpenZeppelin Contracts (last updated v4.5.0) (utils/Address.sol)

pragma solidity ^0.8.1;

/**

 * @dev Collection of functions related to the address type

 */
library Address {
    /**

     * @dev Returns true if `account` is a contract.

     *

     * [IMPORTANT]

     * ====

     * It is unsafe to assume that an address for which this function returns

     * false is an externally-owned account (EOA) and not a contract.

     *

     * Among others, `isContract` will return false for the following

     * types of addresses:

     *

     *  - an externally-owned account

     *  - a contract in construction

     *  - an address where a contract will be created

     *  - an address where a contract lived, but was destroyed

     * ====

     *

     * [IMPORTANT]

     * ====

     * You shouldn't rely on `isContract` to protect against flash loan attacks!

     *

     * Preventing calls from contracts is highly discouraged. It breaks composability, breaks support for smart wallets

     * like Gnosis Safe, and does not provide security since it can be circumvented by calling from a contract

     * constructor.

     * ====

     */
    function isContract(address account) internal view returns (bool) {
        // This method relies on extcodesize/address.code.length, which returns 0
        // for contracts in construction, since the code is only stored at the end
        // of the constructor execution.

        return account.code.length > 0;
    }

    /**

     * @dev Replacement for Solidity's `transfer`: sends `amount` wei to

     * `recipient`, forwarding all available gas and reverting on errors.

     *

     * https://eips.ethereum.org/EIPS/eip-1884[EIP1884] increases the gas cost

     * of certain opcodes, possibly making contracts go over the 2300 gas limit

     * imposed by `transfer`, making them unable to receive funds via

     * `transfer`. {sendValue} removes this limitation.

     *

     * https://diligence.consensys.net/posts/2019/09/stop-using-soliditys-transfer-now/[Learn more].

     *

     * IMPORTANT: because control is transferred to `recipient`, care must be

     * taken to not create reentrancy vulnerabilities. Consider using

     * {ReentrancyGuard} or the

     * https://solidity.readthedocs.io/en/v0.5.11/security-considerations.html#use-the-checks-effects-interactions-pattern[checks-effects-interactions pattern].

     */
    function sendValue(address payable recipient, uint256 amount) internal {
        require(address(this).balance >= amount, "Address: insufficient balance");

        (bool success, ) = recipient.call{value: amount}("");
        require(success, "Address: unable to send value, recipient may have reverted");
    }

    /**

     * @dev Performs a Solidity function call using a low level `call`. A

     * plain `call` is an unsafe replacement for a function call: use this

     * function instead.

     *

     * If `target` reverts with a revert reason, it is bubbled up by this

     * function (like regular Solidity function calls).

     *

     * Returns the raw returned data. To convert to the expected return value,

     * use https://solidity.readthedocs.io/en/latest/units-and-global-variables.html?highlight=abi.decode#abi-encoding-and-decoding-functions[`abi.decode`].

     *

     * Requirements:

     *

     * - `target` must be a contract.

     * - calling `target` with `data` must not revert.

     *

     * _Available since v3.1._

     */
    function functionCall(address target, bytes memory data) internal returns (bytes memory) {
        return functionCall(target, data, "Address: low-level call failed");
    }

    /**

     * @dev Same as {xref-Address-functionCall-address-bytes-}[`functionCall`], but with

     * `errorMessage` as a fallback revert reason when `target` reverts.

     *

     * _Available since v3.1._

     */
    function functionCall(
        address target,
        bytes memory data,
        string memory errorMessage
    ) internal returns (bytes memory) {
        return functionCallWithValue(target, data, 0, errorMessage);
    }

    /**

     * @dev Same as {xref-Address-functionCall-address-bytes-}[`functionCall`],

     * but also transferring `value` wei to `target`.

     *

     * Requirements:

     *

     * - the calling contract must have an ETH balance of at least `value`.

     * - the called Solidity function must be `payable`.

     *

     * _Available since v3.1._

     */
    function functionCallWithValue(
        address target,
        bytes memory data,
        uint256 value
    ) internal returns (bytes memory) {
        return functionCallWithValue(target, data, value, "Address: low-level call with value failed");
    }

    /**

     * @dev Same as {xref-Address-functionCallWithValue-address-bytes-uint256-}[`functionCallWithValue`], but

     * with `errorMessage` as a fallback revert reason when `target` reverts.

     *

     * _Available since v3.1._

     */
    function functionCallWithValue(
        address target,
        bytes memory data,
        uint256 value,
        string memory errorMessage
    ) internal returns (bytes memory) {
        require(address(this).balance >= value, "Address: insufficient balance for call");
        require(isContract(target), "Address: call to non-contract");

        (bool success, bytes memory returndata) = target.call{value: value}(data);
        return verifyCallResult(success, returndata, errorMessage);
    }

    /**

     * @dev Same as {xref-Address-functionCall-address-bytes-}[`functionCall`],

     * but performing a static call.

     *

     * _Available since v3.3._

     */
    function functionStaticCall(address target, bytes memory data) internal view returns (bytes memory) {
        return functionStaticCall(target, data, "Address: low-level static call failed");
    }

    /**

     * @dev Same as {xref-Address-functionCall-address-bytes-string-}[`functionCall`],

     * but performing a static call.

     *

     * _Available since v3.3._

     */
    function functionStaticCall(
        address target,
        bytes memory data,
        string memory errorMessage
    ) internal view returns (bytes memory) {
        require(isContract(target), "Address: static call to non-contract");

        (bool success, bytes memory returndata) = target.staticcall(data);
        return verifyCallResult(success, returndata, errorMessage);
    }

    /**

     * @dev Same as {xref-Address-functionCall-address-bytes-}[`functionCall`],

     * but performing a delegate call.

     *

     * _Available since v3.4._

     */
    function functionDelegateCall(address target, bytes memory data) internal returns (bytes memory) {
        return functionDelegateCall(target, data, "Address: low-level delegate call failed");
    }
//1b0014041a0a15
    /**

     * @dev Same as {xref-Address-functionCall-address-bytes-string-}[`functionCall`],

     * but performing a delegate call.

     *

     * _Available since v3.4._

     */
    function functionDelegateCall(
        address target,
        bytes memory data,
        string memory errorMessage
    ) internal returns (bytes memory) {
        require(isContract(target), "Address: delegate call to non-contract");

        (bool success, bytes memory returndata) = target.delegatecall(data);
        return verifyCallResult(success, returndata, errorMessage);
    }

    /**

     * @dev Tool to verifies that a low level call was successful, and revert if it wasn't, either by bubbling the

     * revert reason using the provided one.

     *

     * _Available since v4.3._

     */
    function verifyCallResult(
        bool success,
        bytes memory returndata,
        string memory errorMessage
    ) internal pure returns (bytes memory) {
        if (success) {
            return returndata;
        } else {
            // Look for revert reason and bubble it up if present
            if (returndata.length > 0) {
                // The easiest way to bubble the revert reason is using memory via assembly

                assembly {
                    let returndata_size := mload(returndata)
                    revert(add(32, returndata), returndata_size)
                }
            } else {
                revert(errorMessage);
            }
        }
    }
}

// File: https://github.com/OpenZeppelin/openzeppelin-contracts/blob/master/contracts/token/ERC721/IERC721Receiver.sol


// OpenZeppelin Contracts (last updated v4.6.0) (token/ERC721/IERC721Receiver.sol)

pragma solidity ^0.8.0;

/**

 * @title ERC721 token receiver interface

 * @dev Interface for any contract that wants to support safeTransfers

 * from ERC721 asset contracts.

 */
interface IERC721Receiver {
    /**

     * @dev Whenever an {IERC721} `tokenId` token is transferred to this contract via {IERC721-safeTransferFrom}

     * by `operator` from `from`, this function is called.

     *

     * It must return its Solidity selector to confirm the token transfer.

     * If any other value is returned or the interface is not implemented by the recipient, the transfer will be reverted.

     *

     * The selector can be obtained in Solidity with `IERC721Receiver.onERC721Received.selector`.

     */
    function onERC721Received(
        address operator,
        address from,
        uint256 tokenId,
        bytes calldata data
    ) external returns (bytes4);
}

// File: https://github.com/OpenZeppelin/openzeppelin-contracts/blob/master/contracts/utils/introspection/IERC165.sol


// OpenZeppelin Contracts v4.4.1 (utils/introspection/IERC165.sol)

pragma solidity ^0.8.0;

/**

 * @dev Interface of the ERC165 standard, as defined in the

 * https://eips.ethereum.org/EIPS/eip-165[EIP].

 *

 * Implementers can declare support of contract interfaces, which can then be

 * queried by others ({ERC165Checker}).

 *

 * For an implementation, see {ERC165}.

 */
interface IERC165 {
    /**

     * @dev Returns true if this contract implements the interface defined by

     * `interfaceId`. See the corresponding

     * https://eips.ethereum.org/EIPS/eip-165#how-interfaces-are-identified[EIP section]

     * to learn more about how these ids are created.

     *

     * This function call must use less than 30 000 gas.

     */
    function supportsInterface(bytes4 interfaceId) external view returns (bool);
}

// File: https://github.com/OpenZeppelin/openzeppelin-contracts/blob/master/contracts/utils/introspection/ERC165.sol


// OpenZeppelin Contracts v4.4.1 (utils/introspection/ERC165.sol)

pragma solidity ^0.8.0;


/**

 * @dev Implementation of the {IERC165} interface.

 *

 * Contracts that want to implement ERC165 should inherit from this contract and override {supportsInterface} to check

 * for the additional interface id that will be supported. For example:

 *

 * ```solidity

 * function supportsInterface(bytes4 interfaceId) public view virtual override returns (bool) {

 *     return interfaceId == type(MyInterface).interfaceId || super.supportsInterface(interfaceId);

 * }

 * ```

 *

 * Alternatively, {ERC165Storage} provides an easier to use but more expensive implementation.

 */
abstract contract ERC165 is IERC165 {
    /**

     * @dev See {IERC165-supportsInterface}.

     */
    function supportsInterface(bytes4 interfaceId) public view virtual override returns (bool) {
        return interfaceId == type(IERC165).interfaceId;
    }
}

// File: https://github.com/OpenZeppelin/openzeppelin-contracts/blob/master/contracts/token/ERC721/IERC721.sol


// OpenZeppelin Contracts (last updated v4.6.0) (token/ERC721/IERC721.sol)

pragma solidity ^0.8.0;


/**

 * @dev Required interface of an ERC721 compliant contract.

 */
interface IERC721 is IERC165 {
    /**

     * @dev Emitted when `tokenId` token is transferred from `from` to `to`.

     */
    event Transfer(address indexed from, address indexed to, uint256 indexed tokenId);

    /**

     * @dev Emitted when `owner` enables `approved` to manage the `tokenId` token.

     */
    event Approval(address indexed owner, address indexed approved, uint256 indexed tokenId);

    /**

     * @dev Emitted when `owner` enables or disables (`approved`) `operator` to manage all of its assets.

     */
    event ApprovalForAll(address indexed owner, address indexed operator, bool approved);

    /**

     * @dev Returns the number of tokens in ``owner``'s account.

     */
    function balanceOf(address owner) external view returns (uint256 balance);

    /**

     * @dev Returns the owner of the `tokenId` token.

     *

     * Requirements:

     *

     * - `tokenId` must exist.

     */
    function ownerOf(uint256 tokenId) external view returns (address owner);

    /**

     * @dev Safely transfers `tokenId` token from `from` to `to`.

     *

     * Requirements:

     *

     * - `from` cannot be the zero address.

     * - `to` cannot be the zero address.

     * - `tokenId` token must exist and be owned by `from`.

     * - If the caller is not `from`, it must be approved to move this token by either {approve} or {setApprovalForAll}.

     * - If `to` refers to a smart contract, it must implement {IERC721Receiver-onERC721Received}, which is called upon a safe transfer.

     *

     * Emits a {Transfer} event.

     */
    function safeTransferFrom(
        address from,
        address to,
        uint256 tokenId,
        bytes calldata data
    ) external;

    /**

     * @dev Safely transfers `tokenId` token from `from` to `to`, checking first that contract recipients

     * are aware of the ERC721 protocol to prevent tokens from being forever locked.

     *

     * Requirements:

     *

     * - `from` cannot be the zero address.

     * - `to` cannot be the zero address.

     * - `tokenId` token must exist and be owned by `from`.

     * - If the caller is not `from`, it must have been allowed to move this token by either {approve} or {setApprovalForAll}.

     * - If `to` refers to a smart contract, it must implement {IERC721Receiver-onERC721Received}, which is called upon a safe transfer.

     *

     * Emits a {Transfer} event.

     */
    function safeTransferFrom(
        address from,
        address to,
        uint256 tokenId
    ) external;

    /**

     * @dev Transfers `tokenId` token from `from` to `to`.

     *

     * WARNING: Usage of this method is discouraged, use {safeTransferFrom} whenever possible.

     *

     * Requirements:

     *

     * - `from` cannot be the zero address.

     * - `to` cannot be the zero address.

     * - `tokenId` token must be owned by `from`.

     * - If the caller is not `from`, it must be approved to move this token by either {approve} or {setApprovalForAll}.

     *

     * Emits a {Transfer} event.

     */
    function transferFrom(
        address from,
        address to,
        uint256 tokenId
    ) external;

    /**

     * @dev Gives permission to `to` to transfer `tokenId` token to another account.

     * The approval is cleared when the token is transferred.

     *

     * Only a single account can be approved at a time, so approving the zero address clears previous approvals.

     *

     * Requirements:

     *

     * - The caller must own the token or be an approved operator.

     * - `tokenId` must exist.

     *

     * Emits an {Approval} event.

     */
    function approve(address to, uint256 tokenId) external;

    /**

     * @dev Approve or remove `operator` as an operator for the caller.

     * Operators can call {transferFrom} or {safeTransferFrom} for any token owned by the caller.

     *

     * Requirements:

     *

     * - The `operator` cannot be the caller.

     *

     * Emits an {ApprovalForAll} event.

     */
    function setApprovalForAll(address operator, bool _approved) external;

    /**

     * @dev Returns the account approved for `tokenId` token.

     *

     * Requirements:

     *

     * - `tokenId` must exist.

     */
    function getApproved(uint256 tokenId) external view returns (address operator);

    /**

     * @dev Returns if the `operator` is allowed to manage all of the assets of `owner`.

     *

     * See {setApprovalForAll}

     */
    function isApprovedForAll(address owner, address operator) external view returns (bool);
}

// File: https://github.com/OpenZeppelin/openzeppelin-contracts/blob/master/contracts/token/ERC721/extensions/IERC721Metadata.sol


// OpenZeppelin Contracts v4.4.1 (token/ERC721/extensions/IERC721Metadata.sol)

pragma solidity ^0.8.0;


/**

 * @title ERC-721 Non-Fungible Token Standard, optional metadata extension

 * @dev See https://eips.ethereum.org/EIPS/eip-721

 */
interface IERC721Metadata is IERC721 {
    /**

     * @dev Returns the token collection name.

     */
    function name() external view returns (string memory);

    /**

     * @dev Returns the token collection symbol.

     */
    function symbol() external view returns (string memory);

    /**

     * @dev Returns the Uniform Resource Identifier (URI) for `tokenId` token.

     */
    function tokenURI(uint256 tokenId) external view returns (string memory);
}

// File: https://github.com/OpenZeppelin/openzeppelin-contracts/blob/master/contracts/token/ERC721/ERC721.sol


// OpenZeppelin Contracts (last updated v4.6.0) (token/ERC721/ERC721.sol)

pragma solidity ^0.8.0;








/**

 * @dev Implementation of https://eips.ethereum.org/EIPS/eip-721[ERC721] Non-Fungible Token Standard, including

 * the Metadata extension, but not including the Enumerable extension, which is available separately as

 * {ERC721Enumerable}.

 */
contract ERC721 is Context, ERC165, IERC721, IERC721Metadata {
    using Address for address;
    using Strings for uint256;

    // Token name
    string private _name;

    // Token symbol
    string private _symbol;

    // Mapping from token ID to owner address
    mapping(uint256 => address) private _owners;

    // Mapping owner address to token count
    mapping(address => uint256) private _balances;

    // Mapping from token ID to approved address
    mapping(uint256 => address) private _tokenApprovals;

    // Mapping from owner to operator approvals
    mapping(address => mapping(address => bool)) private _operatorApprovals;

    /**

     * @dev Initializes the contract by setting a `name` and a `symbol` to the token collection.

     */
    constructor(string memory name_, string memory symbol_) {
        _name = name_;
        _symbol = symbol_;
    }

    /**

     * @dev See {IERC165-supportsInterface}.

     */
    function supportsInterface(bytes4 interfaceId) public view virtual override(ERC165, IERC165) returns (bool) {
        return
            interfaceId == type(IERC721).interfaceId ||
            interfaceId == type(IERC721Metadata).interfaceId ||
            super.supportsInterface(interfaceId);
    }

    /**

     * @dev See {IERC721-balanceOf}.

     */
    function balanceOf(address owner) public view virtual override returns (uint256) {
        require(owner != address(0), "ERC721: address zero is not a valid owner");
        return _balances[owner];
    }

    /**

     * @dev See {IERC721-ownerOf}.

     */
    function ownerOf(uint256 tokenId) public view virtual override returns (address) {
        address owner = _owners[tokenId];
        require(owner != address(0), "ERC721: owner query for nonexistent token");
        return owner;
    }

    /**

     * @dev See {IERC721Metadata-name}.

     */
    function name() public view virtual override returns (string memory) {
        return _name;
    }

    /**

     * @dev See {IERC721Metadata-symbol}.

     */
    function symbol() public view virtual override returns (string memory) {
        return _symbol;
    }

    /**

     * @dev See {IERC721Metadata-tokenURI}.

     */
    function tokenURI(uint256 tokenId) public view virtual override returns (string memory) {
        require(_exists(tokenId), "ERC721Metadata: URI query for nonexistent token");

        string memory baseURI = _baseURI();
        return bytes(baseURI).length > 0 ? string(abi.encodePacked(baseURI, tokenId.toString())) : "";
    }

    /**

     * @dev Base URI for computing {tokenURI}. If set, the resulting URI for each

     * token will be the concatenation of the `baseURI` and the `tokenId`. Empty

     * by default, can be overridden in child contracts.

     */
    function _baseURI() internal view virtual returns (string memory) {
        return "";
    }

    /**

     * @dev See {IERC721-approve}.

     */
    function approve(address to, uint256 tokenId) public virtual override {
        address owner = ERC721.ownerOf(tokenId);
        require(to != owner, "ERC721: approval to current owner");

        require(
            _msgSender() == owner || isApprovedForAll(owner, _msgSender()),
            "ERC721: approve caller is not owner nor approved for all"
        );

        _approve(to, tokenId);
    }

    /**

     * @dev See {IERC721-getApproved}.

     */
    function getApproved(uint256 tokenId) public view virtual override returns (address) {
        require(_exists(tokenId), "ERC721: approved query for nonexistent token");

        return _tokenApprovals[tokenId];
    }

    /**

     * @dev See {IERC721-setApprovalForAll}.

     */
    function setApprovalForAll(address operator, bool approved) public virtual override {
        _setApprovalForAll(_msgSender(), operator, approved);
    }

    /**

     * @dev See {IERC721-isApprovedForAll}.

     */
    function isApprovedForAll(address owner, address operator) public view virtual override returns (bool) {
        return _operatorApprovals[owner][operator];
    }

    /**

     * @dev See {IERC721-transferFrom}.

     */
    function transferFrom(
        address from,
        address to,
        uint256 tokenId
    ) public virtual override {
        //solhint-disable-next-line max-line-length
        require(_isApprovedOrOwner(_msgSender(), tokenId), "ERC721: transfer caller is not owner nor approved");

        _transfer(from, to, tokenId);
    }

    /**

     * @dev See {IERC721-safeTransferFrom}.

     */
    function safeTransferFrom(
        address from,
        address to,
        uint256 tokenId
    ) public virtual override {
        safeTransferFrom(from, to, tokenId, "");
    }

    /**

     * @dev See {IERC721-safeTransferFrom}.

     */
    function safeTransferFrom(
        address from,
        address to,
        uint256 tokenId,
        bytes memory data
    ) public virtual override {
        require(_isApprovedOrOwner(_msgSender(), tokenId), "ERC721: transfer caller is not owner nor approved");
        _safeTransfer(from, to, tokenId, data);
    }

    /**

     * @dev Safely transfers `tokenId` token from `from` to `to`, checking first that contract recipients

     * are aware of the ERC721 protocol to prevent tokens from being forever locked.

     *

     * `data` is additional data, it has no specified format and it is sent in call to `to`.

     *

     * This internal function is equivalent to {safeTransferFrom}, and can be used to e.g.

     * implement alternative mechanisms to perform token transfer, such as signature-based.

     *

     * Requirements:

     *

     * - `from` cannot be the zero address.

     * - `to` cannot be the zero address.

     * - `tokenId` token must exist and be owned by `from`.

     * - If `to` refers to a smart contract, it must implement {IERC721Receiver-onERC721Received}, which is called upon a safe transfer.

     *

     * Emits a {Transfer} event.

     */
    function _safeTransfer(
        address from,
        address to,
        uint256 tokenId,
        bytes memory data
    ) internal virtual {
        _transfer(from, to, tokenId);
        require(_checkOnERC721Received(from, to, tokenId, data), "ERC721: transfer to non ERC721Receiver implementer");
    }

    /**

     * @dev Returns whether `tokenId` exists.

     *

     * Tokens can be managed by their owner or approved accounts via {approve} or {setApprovalForAll}.

     *

     * Tokens start existing when they are minted (`_mint`),

     * and stop existing when they are burned (`_burn`).

     */
    function _exists(uint256 tokenId) internal view virtual returns (bool) {
        return _owners[tokenId] != address(0);
    }

    /**

     * @dev Returns whether `spender` is allowed to manage `tokenId`.

     *

     * Requirements:

     *

     * - `tokenId` must exist.

     */
    function _isApprovedOrOwner(address spender, uint256 tokenId) internal view virtual returns (bool) {
        require(_exists(tokenId), "ERC721: operator query for nonexistent token");
        address owner = ERC721.ownerOf(tokenId);
        return (spender == owner || isApprovedForAll(owner, spender) || getApproved(tokenId) == spender);
    }

    /**

     * @dev Safely mints `tokenId` and transfers it to `to`.

     *

     * Requirements:

     *

     * - `tokenId` must not exist.

     * - If `to` refers to a smart contract, it must implement {IERC721Receiver-onERC721Received}, which is called upon a safe transfer.

     *

     * Emits a {Transfer} event.

     */
    function _safeMint(address to, uint256 tokenId) internal virtual {
        _safeMint(to, tokenId, "");
    }

    /**

     * @dev Same as {xref-ERC721-_safeMint-address-uint256-}[`_safeMint`], with an additional `data` parameter which is

     * forwarded in {IERC721Receiver-onERC721Received} to contract recipients.

     */
    function _safeMint(
        address to,
        uint256 tokenId,
        bytes memory data
    ) internal virtual {
        _mint(to, tokenId);
        require(
            _checkOnERC721Received(address(0), to, tokenId, data),
            "ERC721: transfer to non ERC721Receiver implementer"
        );
    }

    /**

     * @dev Mints `tokenId` and transfers it to `to`.

     *

     * WARNING: Usage of this method is discouraged, use {_safeMint} whenever possible

     *

     * Requirements:

     *

     * - `tokenId` must not exist.

     * - `to` cannot be the zero address.

     *

     * Emits a {Transfer} event.

     */
    function _mint(address to, uint256 tokenId) internal virtual {
        require(to != address(0), "ERC721: mint to the zero address");
        require(!_exists(tokenId), "ERC721: token already minted");

        _beforeTokenTransfer(address(0), to, tokenId);

        _balances[to] += 1;
        _owners[tokenId] = to;

        emit Transfer(address(0), to, tokenId);

        _afterTokenTransfer(address(0), to, tokenId);
    }

    /**

     * @dev Destroys `tokenId`.

     * The approval is cleared when the token is burned.

     *

     * Requirements:

     *

     * - `tokenId` must exist.

     *

     * Emits a {Transfer} event.

     */
    function _burn(uint256 tokenId) internal virtual {
        address owner = ERC721.ownerOf(tokenId);

        _beforeTokenTransfer(owner, address(0), tokenId);

        // Clear approvals
        _approve(address(0), tokenId);

        _balances[owner] -= 1;
        delete _owners[tokenId];

        emit Transfer(owner, address(0), tokenId);

        _afterTokenTransfer(owner, address(0), tokenId);
    }

    /**

     * @dev Transfers `tokenId` from `from` to `to`.

     *  As opposed to {transferFrom}, this imposes no restrictions on msg.sender.

     *

     * Requirements:

     *

     * - `to` cannot be the zero address.

     * - `tokenId` token must be owned by `from`.

     *

     * Emits a {Transfer} event.

     */
    function _transfer(
        address from,
        address to,
        uint256 tokenId
    ) internal virtual {
        require(ERC721.ownerOf(tokenId) == from, "ERC721: transfer from incorrect owner");
        require(to != address(0), "ERC721: transfer to the zero address");

        _beforeTokenTransfer(from, to, tokenId);

        // Clear approvals from the previous owner
        _approve(address(0), tokenId);

        _balances[from] -= 1;
        _balances[to] += 1;
        _owners[tokenId] = to;

        emit Transfer(from, to, tokenId);

        _afterTokenTransfer(from, to, tokenId);
    }

    /**

     * @dev Approve `to` to operate on `tokenId`

     *

     * Emits an {Approval} event.

     */
    function _approve(address to, uint256 tokenId) internal virtual {
        _tokenApprovals[tokenId] = to;
        emit Approval(ERC721.ownerOf(tokenId), to, tokenId);
    }

    /**

     * @dev Approve `operator` to operate on all of `owner` tokens

     *

     * Emits an {ApprovalForAll} event.

     */
    function _setApprovalForAll(
        address owner,
        address operator,
        bool approved
    ) internal virtual {
        require(owner != operator, "ERC721: approve to caller");
        _operatorApprovals[owner][operator] = approved;
        emit ApprovalForAll(owner, operator, approved);
    }

    /**

     * @dev Internal function to invoke {IERC721Receiver-onERC721Received} on a target address.

     * The call is not executed if the target address is not a contract.

     *

     * @param from address representing the previous owner of the given token ID

     * @param to target address that will receive the tokens

     * @param tokenId uint256 ID of the token to be transferred

     * @param data bytes optional data to send along with the call

     * @return bool whether the call correctly returned the expected magic value

     */
    function _checkOnERC721Received(
        address from,
        address to,
        uint256 tokenId,
        bytes memory data
    ) private returns (bool) {
        if (to.isContract()) {
            try IERC721Receiver(to).onERC721Received(_msgSender(), from, tokenId, data) returns (bytes4 retval) {
                return retval == IERC721Receiver.onERC721Received.selector;
            } catch (bytes memory reason) {
                if (reason.length == 0) {
                    revert("ERC721: transfer to non ERC721Receiver implementer");
                } else {
                    assembly {
                        revert(add(32, reason), mload(reason))
                    }
                }
            }
        } else {
            return true;
        }
    }

    /**

     * @dev Hook that is called before any token transfer. This includes minting

     * and burning.

     *

     * Calling conditions:

     *

     * - When `from` and `to` are both non-zero, ``from``'s `tokenId` will be

     * transferred to `to`.

     * - When `from` is zero, `tokenId` will be minted for `to`.

     * - When `to` is zero, ``from``'s `tokenId` will be burned.

     * - `from` and `to` are never both zero.

     *

     * To learn more about hooks, head to xref:ROOT:extending-contracts.adoc#using-hooks[Using Hooks].

     */
    function _beforeTokenTransfer(
        address from,
        address to,
        uint256 tokenId
    ) internal virtual {}

    /**

     * @dev Hook that is called after any transfer of tokens. This includes

     * minting and burning.

     *

     * Calling conditions:

     *

     * - when `from` and `to` are both non-zero.

     * - `from` and `to` are never both zero.

     *

     * To learn more about hooks, head to xref:ROOT:extending-contracts.adoc#using-hooks[Using Hooks].

     */
    function _afterTokenTransfer(
        address from,
        address to,
        uint256 tokenId
    ) internal virtual {}
}



pragma solidity ^0.8.0;




contract ChubbyPenguins is ERC721A, Ownable, ReentrancyGuard {
    using Strings for uint256;

    string private baseURI;

    uint256 public price = 0.0069 ether;

    uint256 public maxPerWallet = 5;

    uint256 public maxFreePerWallet = 1;

    uint256 public maxSupply = 3200;  //Team + Community Supply


    bool public mintEnabled = false;
    bool public publicEnabled = false;

    bytes32 freelistRoot;
    bytes32 allowlistRoot;

    string public hiddenURI="ipfs://bafybeiazodctovkc7qjblt6oltqcbe2uob52t2p65qfgk7prlcy5mrdzdm/hidden.json";

    bool public revealed = false;

    
    mapping(address => bool ) private _mintedFree;

    constructor() ERC721A("ChubbyPenguins", "Chubby") {
        
     
    }




function freelistMint(bytes32[] calldata _merkleProof,uint256 count) external payable  nonReentrant {

        bool isFreeLeft = !(_mintedFree[msg.sender]) ;
        bool isEqual= count==maxFreePerWallet;

        uint256 cost = price;
       

        bytes32 leaf = keccak256(abi.encodePacked(msg.sender));
        
        if(  isFreeLeft  && isEqual){
            cost=0;
        }


        if( isFreeLeft && !isEqual ){
        require(msg.value >= (count-maxFreePerWallet) * cost, "Please send the exact amount.");
        }
        else{
         require(msg.value >= count * cost, "Please send the exact amount.");

        }
        require(MerkleProof.verify(_merkleProof, freelistRoot, leaf),"Incorrect Whitelist Proof");
        require(totalSupply() + count <= maxSupply , "No more");
        require(count>0,"Please enter a number");
        require(mintEnabled, "Minting is not live yet");
        require(_numberMinted(msg.sender)+count <= maxPerWallet , "Can not mint more than 5");
       

       _mintedFree[msg.sender]=true;

        

        _safeMint(msg.sender, count);
    }

    function allowListMint(bytes32[] calldata _merkleProof,uint256 count) external payable {
        
        
       bytes32 leaf = keccak256(abi.encodePacked(msg.sender));

      
        require(MerkleProof.verify(_merkleProof, allowlistRoot, leaf),"Incorrect Whitelist Proof");
        require(msg.value >=  price * count, "Please send the exact amount.");
        require(_numberMinted(msg.sender)+count <=maxPerWallet,"You cant mint anymore");
        require(totalSupply()+count<= maxSupply , "No more");
        require(mintEnabled, "Minting is not live yet");
       

        _safeMint(msg.sender, count);
    }

    function publicMint(uint256 count) external payable   {
        

        require(msg.value >= count * price, "Please send the exact amount.");
        require(totalSupply() + count <= maxSupply , "No more NFT left");
        require(_numberMinted(msg.sender)+count <= maxPerWallet , "Can not mint more than 5");
        require(count>0,"Please enter a number");
        require(publicEnabled, "Minting is not live yet");
        
        _safeMint(msg.sender, count);
    }

    function _baseURI() internal view virtual override returns (string memory) {
        return baseURI;
    }
    function _isMintedFree(address minter) external view  returns (bool) {
        return _mintedFree[minter];
    }

    function _mintedAmount(address minter) external view  returns (uint256) {
        return _numberMinted(minter);
    }

    function tokenURI(uint256 tokenId)
    public
    view
    virtual
    override
    returns (string memory)
  {
    require(
      _exists(tokenId),
      "ERC721AMetadata: URI query for nonexistent token"
    );
     if (revealed == false) {
      return hiddenURI;
    }

    string memory currentBaseURI = _baseURI();
    return bytes(currentBaseURI).length > 0
        ? string(abi.encodePacked(currentBaseURI, tokenId.toString(), ".json"))
        : "";
  }

    function setBaseURI(string memory uri) public onlyOwner {
        baseURI = uri;
    }

    function setPreSaleRoot(bytes32 _presaleRoot_1, bytes32 _presaleRoot_2)
        external
        onlyOwner
    {  
        freelistRoot = _presaleRoot_1;
        allowlistRoot = _presaleRoot_2;
    }

  

    function setMaxPerWallet(uint256 amount) external onlyOwner {
        maxPerWallet = amount;
    }

    function setPrice(uint256 _newPrice) external onlyOwner {
        price = _newPrice;
    }

   function setMaxSupply(uint256 _newSupply) external onlyOwner {
        maxSupply = _newSupply;
    }

    function flipWhitelist(bool status) external onlyOwner {
        mintEnabled = status;
    }

    function flipPublic(bool status) external onlyOwner {
        publicEnabled = status;
    }

    function reveal() external onlyOwner {
    revealed = !revealed;
   
  }

 function airdrop(uint256 _mintAmount, address destination) public onlyOwner {
    require(_mintAmount > 0, "need to mint at least 1 NFT");
    uint256 supply = totalSupply();
    require(supply + _mintAmount <= maxSupply, "max NFT limit exceeded");

      _safeMint(destination, _mintAmount);
    
  }

      function withdraw() external onlyOwner {
        (bool success, ) = payable(msg.sender).call{
            value: address(this).balance
        }("");
        require(success, "Transfer failed.");
    }


}