organized_contracts/1c/1c06da06ae89552fad3c9ebf18ee93d9bc451f640fb13855525c78e604b4b137/contract.json

{
  "language": "Solidity",
  "sources": {
    "contracts/Feetsies.sol": {
      "content": "// SPDX-License-Identifier: MIT\npragma solidity ^0.8.14;\n\nimport \"erc721a/contracts/ERC721A.sol\";\nimport \"@openzeppelin/contracts/access/Ownable.sol\";\nimport \"@openzeppelin/contracts/utils/cryptography/MerkleProof.sol\";\nimport \"@openzeppelin/contracts/utils/Strings.sol\";\n\ncontract Feetsies is ERC721A, Ownable {\n    using Strings for uint256;\n\n    uint256 public MAX_SUPPLY = 4000;\n    uint256 public MAX_PUBLIC_SUPPLY = 3250;\n    uint256 public MAX_PUBLIC_MINT = 5;\n    uint256 public MAX_WHITELIST_MINT = 1;\n    uint256 public PUBLIC_SALE_PRICE = .003 ether;\n    uint256 public WHITELIST_SALE_PRICE = 0 ether;\n\n    string private baseTokenUri = \"\";\n    string public hiddenTokenUri = \"ipfs://QmXc2fGKp7ong2gqLYFuAMuUx4oz6K5rRtq3k2HP3VHTFq/unrevealed.json\";\n\n    bool public isRevealed;\n\n    enum MintStage {\n        PAUSED,\n        PUBLIC,\n        WHITELIST\n    }\n\n    MintStage public stage = MintStage.PAUSED;\n\n    bytes32 private merkleRoot;\n\n    mapping(address => uint256) public totalWhitelistMint;\n\n    constructor() ERC721A(\"Feetsies\", \"FEET\") {}\n\n    function mint(uint256 _quantity) external payable {\n        require(stage == MintStage.PUBLIC, \"Public sale is not active yet\");\n        require(\n            (totalSupply() + _quantity) <= MAX_PUBLIC_SUPPLY,\n            \"Beyond max public supply\"\n        );\n        require(\n            _quantity <= MAX_PUBLIC_MINT,\n            \"You can not mint more than max per transaction\"\n        );\n        require(\n            msg.value >= (PUBLIC_SALE_PRICE * _quantity),\n            \"Wrong mint price\"\n        );\n\n        _safeMint(msg.sender, _quantity);\n    }\n\n    function whitelistMint(bytes32[] memory _merkleProof, uint256 _quantity)\n        external\n        payable\n    {\n        require(\n            stage == MintStage.WHITELIST,\n            \"Whitelist sale is not active yet\"\n        );\n        require((totalSupply() + _quantity) <= MAX_SUPPLY, \"Beyond max supply\");\n        require(\n            (totalWhitelistMint[msg.sender] + _quantity) <= MAX_WHITELIST_MINT,\n            \"You can not mint any more with this wallet\"\n        );\n        require(\n            msg.value >= (WHITELIST_SALE_PRICE * _quantity),\n            \"Wrong mint price\"\n        );\n        //create leaf node\n        bytes32 sender = keccak256(abi.encodePacked(msg.sender));\n        require(\n            MerkleProof.verify(_merkleProof, merkleRoot, sender),\n            \"You are not whitelisted.\"\n        );\n\n        totalWhitelistMint[msg.sender] += _quantity;\n        _safeMint(msg.sender, _quantity);\n    }\n\n    function teamMint(address receiver, uint256 mintAmount) external onlyOwner {\n        _safeMint(receiver, mintAmount);\n    }\n\n    function _baseURI() internal view virtual override returns (string memory) {\n        return baseTokenUri;\n    }\n\n    function tokenURI(uint256 tokenId)\n        public\n        view\n        virtual\n        override\n        returns (string memory)\n    {\n        require(\n            _exists(tokenId),\n            \"ERC721Metadata: URI query for nonexistent token\"\n        );\n\n        uint256 trueId = tokenId + 1;\n\n        if (!isRevealed) {\n            return hiddenTokenUri;\n        }\n        //string memory baseURI = _baseURI();\n        return\n            bytes(baseTokenUri).length > 0\n                ? string(\n                    abi.encodePacked(baseTokenUri, trueId.toString(), \".json\")\n                )\n                : \"\";\n    }\n\n    function setTokenUri(string memory _baseTokenUri) external onlyOwner {\n        baseTokenUri = _baseTokenUri;\n    }\n\n    function setPlaceHolderUri(string memory _hiddenTokenUri)\n        external\n        onlyOwner\n    {\n        hiddenTokenUri = _hiddenTokenUri;\n    }\n\n    function setMerkleRoot(bytes32 _merkleRoot) external onlyOwner {\n        merkleRoot = _merkleRoot;\n    }\n\n    function getMerkleRoot() external view returns (bytes32) {\n        return merkleRoot;\n    }\n\n    function setMintStage(MintStage _stage) public onlyOwner {\n        stage = _stage;\n    }\n\n    function setWhitelistSalePrice(uint256 newPrice) external onlyOwner {\n        WHITELIST_SALE_PRICE = newPrice;\n    }\n\n    function setPublicSalePrice(uint256 newPrice) external onlyOwner {\n        PUBLIC_SALE_PRICE = newPrice;\n    }\n\n    function setMaxPublicMint(uint256 amount) external onlyOwner {\n        MAX_PUBLIC_MINT = amount;\n    }\n\n    function toggleReveal() external onlyOwner {\n        isRevealed = !isRevealed;\n    }\n\n    function withdraw() external onlyOwner {\n        (bool success, ) = payable(msg.sender).call{\n            value: address(this).balance\n        }(\"\");\n        require(success, \"Withdraw failed.\");\n    }\n}\n"
    },
    "@openzeppelin/contracts/utils/Strings.sol": {
      "content": "// SPDX-License-Identifier: MIT\n// OpenZeppelin Contracts (last updated v4.8.0) (utils/Strings.sol)\n\npragma solidity ^0.8.0;\n\nimport \"./math/Math.sol\";\n\n/**\n * @dev String operations.\n */\nlibrary Strings {\n    bytes16 private constant _SYMBOLS = \"0123456789abcdef\";\n    uint8 private constant _ADDRESS_LENGTH = 20;\n\n    /**\n     * @dev Converts a `uint256` to its ASCII `string` decimal representation.\n     */\n    function toString(uint256 value) internal pure returns (string memory) {\n        unchecked {\n            uint256 length = Math.log10(value) + 1;\n            string memory buffer = new string(length);\n            uint256 ptr;\n            /// @solidity memory-safe-assembly\n            assembly {\n                ptr := add(buffer, add(32, length))\n            }\n            while (true) {\n                ptr--;\n                /// @solidity memory-safe-assembly\n                assembly {\n                    mstore8(ptr, byte(mod(value, 10), _SYMBOLS))\n                }\n                value /= 10;\n                if (value == 0) break;\n            }\n            return buffer;\n        }\n    }\n\n    /**\n     * @dev Converts a `uint256` to its ASCII `string` hexadecimal representation.\n     */\n    function toHexString(uint256 value) internal pure returns (string memory) {\n        unchecked {\n            return toHexString(value, Math.log256(value) + 1);\n        }\n    }\n\n    /**\n     * @dev Converts a `uint256` to its ASCII `string` hexadecimal representation with fixed length.\n     */\n    function toHexString(uint256 value, uint256 length) internal pure returns (string memory) {\n        bytes memory buffer = new bytes(2 * length + 2);\n        buffer[0] = \"0\";\n        buffer[1] = \"x\";\n        for (uint256 i = 2 * length + 1; i > 1; --i) {\n            buffer[i] = _SYMBOLS[value & 0xf];\n            value >>= 4;\n        }\n        require(value == 0, \"Strings: hex length insufficient\");\n        return string(buffer);\n    }\n\n    /**\n     * @dev Converts an `address` with fixed length of 20 bytes to its not checksummed ASCII `string` hexadecimal representation.\n     */\n    function toHexString(address addr) internal pure returns (string memory) {\n        return toHexString(uint256(uint160(addr)), _ADDRESS_LENGTH);\n    }\n}\n"
    },
    "@openzeppelin/contracts/utils/cryptography/MerkleProof.sol": {
      "content": "// SPDX-License-Identifier: MIT\n// OpenZeppelin Contracts (last updated v4.8.0) (utils/cryptography/MerkleProof.sol)\n\npragma solidity ^0.8.0;\n\n/**\n * @dev These functions deal with verification of Merkle Tree proofs.\n *\n * The tree and the proofs can be generated using our\n * https://github.com/OpenZeppelin/merkle-tree[JavaScript library].\n * You will find a quickstart guide in the readme.\n *\n * WARNING: You should avoid using leaf values that are 64 bytes long prior to\n * hashing, or use a hash function other than keccak256 for hashing leaves.\n * This is because the concatenation of a sorted pair of internal nodes in\n * the merkle tree could be reinterpreted as a leaf value.\n * OpenZeppelin's JavaScript library generates merkle trees that are safe\n * against this attack out of the box.\n */\nlibrary MerkleProof {\n    /**\n     * @dev Returns true if a `leaf` can be proved to be a part of a Merkle tree\n     * defined by `root`. For this, a `proof` must be provided, containing\n     * sibling hashes on the branch from the leaf to the root of the tree. Each\n     * pair of leaves and each pair of pre-images are assumed to be sorted.\n     */\n    function verify(\n        bytes32[] memory proof,\n        bytes32 root,\n        bytes32 leaf\n    ) internal pure returns (bool) {\n        return processProof(proof, leaf) == root;\n    }\n\n    /**\n     * @dev Calldata version of {verify}\n     *\n     * _Available since v4.7._\n     */\n    function verifyCalldata(\n        bytes32[] calldata proof,\n        bytes32 root,\n        bytes32 leaf\n    ) internal pure returns (bool) {\n        return processProofCalldata(proof, leaf) == root;\n    }\n\n    /**\n     * @dev Returns the rebuilt hash obtained by traversing a Merkle tree up\n     * from `leaf` using `proof`. A `proof` is valid if and only if the rebuilt\n     * hash matches the root of the tree. When processing the proof, the pairs\n     * of leafs & pre-images are assumed to be sorted.\n     *\n     * _Available since v4.4._\n     */\n    function processProof(bytes32[] memory proof, bytes32 leaf) internal pure returns (bytes32) {\n        bytes32 computedHash = leaf;\n        for (uint256 i = 0; i < proof.length; i++) {\n            computedHash = _hashPair(computedHash, proof[i]);\n        }\n        return computedHash;\n    }\n\n    /**\n     * @dev Calldata version of {processProof}\n     *\n     * _Available since v4.7._\n     */\n    function processProofCalldata(bytes32[] calldata proof, bytes32 leaf) internal pure returns (bytes32) {\n        bytes32 computedHash = leaf;\n        for (uint256 i = 0; i < proof.length; i++) {\n            computedHash = _hashPair(computedHash, proof[i]);\n        }\n        return computedHash;\n    }\n\n    /**\n     * @dev Returns true if the `leaves` can be simultaneously proven to be a part of a merkle tree defined by\n     * `root`, according to `proof` and `proofFlags` as described in {processMultiProof}.\n     *\n     * CAUTION: Not all merkle trees admit multiproofs. See {processMultiProof} for details.\n     *\n     * _Available since v4.7._\n     */\n    function multiProofVerify(\n        bytes32[] memory proof,\n        bool[] memory proofFlags,\n        bytes32 root,\n        bytes32[] memory leaves\n    ) internal pure returns (bool) {\n        return processMultiProof(proof, proofFlags, leaves) == root;\n    }\n\n    /**\n     * @dev Calldata version of {multiProofVerify}\n     *\n     * CAUTION: Not all merkle trees admit multiproofs. See {processMultiProof} for details.\n     *\n     * _Available since v4.7._\n     */\n    function multiProofVerifyCalldata(\n        bytes32[] calldata proof,\n        bool[] calldata proofFlags,\n        bytes32 root,\n        bytes32[] memory leaves\n    ) internal pure returns (bool) {\n        return processMultiProofCalldata(proof, proofFlags, leaves) == root;\n    }\n\n    /**\n     * @dev Returns the root of a tree reconstructed from `leaves` and sibling nodes in `proof`. The reconstruction\n     * proceeds by incrementally reconstructing all inner nodes by combining a leaf/inner node with either another\n     * leaf/inner node or a proof sibling node, depending on whether each `proofFlags` item is true or false\n     * respectively.\n     *\n     * CAUTION: Not all merkle trees admit multiproofs. To use multiproofs, it is sufficient to ensure that: 1) the tree\n     * is complete (but not necessarily perfect), 2) the leaves to be proven are in the opposite order they are in the\n     * tree (i.e., as seen from right to left starting at the deepest layer and continuing at the next layer).\n     *\n     * _Available since v4.7._\n     */\n    function processMultiProof(\n        bytes32[] memory proof,\n        bool[] memory proofFlags,\n        bytes32[] memory leaves\n    ) internal pure returns (bytes32 merkleRoot) {\n        // This function rebuild the root hash by traversing the tree up from the leaves. The root is rebuilt by\n        // consuming and producing values on a queue. The queue starts with the `leaves` array, then goes onto the\n        // `hashes` array. At the end of the process, the last hash in the `hashes` array should contain the root of\n        // the merkle tree.\n        uint256 leavesLen = leaves.length;\n        uint256 totalHashes = proofFlags.length;\n\n        // Check proof validity.\n        require(leavesLen + proof.length - 1 == totalHashes, \"MerkleProof: invalid multiproof\");\n\n        // The xxxPos values are \"pointers\" to the next value to consume in each array. All accesses are done using\n        // `xxx[xxxPos++]`, which return the current value and increment the pointer, thus mimicking a queue's \"pop\".\n        bytes32[] memory hashes = new bytes32[](totalHashes);\n        uint256 leafPos = 0;\n        uint256 hashPos = 0;\n        uint256 proofPos = 0;\n        // At each step, we compute the next hash using two values:\n        // - a value from the \"main queue\". If not all leaves have been consumed, we get the next leaf, otherwise we\n        //   get the next hash.\n        // - depending on the flag, either another value for the \"main queue\" (merging branches) or an element from the\n        //   `proof` array.\n        for (uint256 i = 0; i < totalHashes; i++) {\n            bytes32 a = leafPos < leavesLen ? leaves[leafPos++] : hashes[hashPos++];\n            bytes32 b = proofFlags[i] ? leafPos < leavesLen ? leaves[leafPos++] : hashes[hashPos++] : proof[proofPos++];\n            hashes[i] = _hashPair(a, b);\n        }\n\n        if (totalHashes > 0) {\n            return hashes[totalHashes - 1];\n        } else if (leavesLen > 0) {\n            return leaves[0];\n        } else {\n            return proof[0];\n        }\n    }\n\n    /**\n     * @dev Calldata version of {processMultiProof}.\n     *\n     * CAUTION: Not all merkle trees admit multiproofs. See {processMultiProof} for details.\n     *\n     * _Available since v4.7._\n     */\n    function processMultiProofCalldata(\n        bytes32[] calldata proof,\n        bool[] calldata proofFlags,\n        bytes32[] memory leaves\n    ) internal pure returns (bytes32 merkleRoot) {\n        // This function rebuild the root hash by traversing the tree up from the leaves. The root is rebuilt by\n        // consuming and producing values on a queue. The queue starts with the `leaves` array, then goes onto the\n        // `hashes` array. At the end of the process, the last hash in the `hashes` array should contain the root of\n        // the merkle tree.\n        uint256 leavesLen = leaves.length;\n        uint256 totalHashes = proofFlags.length;\n\n        // Check proof validity.\n        require(leavesLen + proof.length - 1 == totalHashes, \"MerkleProof: invalid multiproof\");\n\n        // The xxxPos values are \"pointers\" to the next value to consume in each array. All accesses are done using\n        // `xxx[xxxPos++]`, which return the current value and increment the pointer, thus mimicking a queue's \"pop\".\n        bytes32[] memory hashes = new bytes32[](totalHashes);\n        uint256 leafPos = 0;\n        uint256 hashPos = 0;\n        uint256 proofPos = 0;\n        // At each step, we compute the next hash using two values:\n        // - a value from the \"main queue\". If not all leaves have been consumed, we get the next leaf, otherwise we\n        //   get the next hash.\n        // - depending on the flag, either another value for the \"main queue\" (merging branches) or an element from the\n        //   `proof` array.\n        for (uint256 i = 0; i < totalHashes; i++) {\n            bytes32 a = leafPos < leavesLen ? leaves[leafPos++] : hashes[hashPos++];\n            bytes32 b = proofFlags[i] ? leafPos < leavesLen ? leaves[leafPos++] : hashes[hashPos++] : proof[proofPos++];\n            hashes[i] = _hashPair(a, b);\n        }\n\n        if (totalHashes > 0) {\n            return hashes[totalHashes - 1];\n        } else if (leavesLen > 0) {\n            return leaves[0];\n        } else {\n            return proof[0];\n        }\n    }\n\n    function _hashPair(bytes32 a, bytes32 b) private pure returns (bytes32) {\n        return a < b ? _efficientHash(a, b) : _efficientHash(b, a);\n    }\n\n    function _efficientHash(bytes32 a, bytes32 b) private pure returns (bytes32 value) {\n        /// @solidity memory-safe-assembly\n        assembly {\n            mstore(0x00, a)\n            mstore(0x20, b)\n            value := keccak256(0x00, 0x40)\n        }\n    }\n}\n"
    },
    "@openzeppelin/contracts/access/Ownable.sol": {
      "content": "// SPDX-License-Identifier: MIT\n// OpenZeppelin Contracts (last updated v4.7.0) (access/Ownable.sol)\n\npragma solidity ^0.8.0;\n\nimport \"../utils/Context.sol\";\n\n/**\n * @dev Contract module which provides a basic access control mechanism, where\n * there is an account (an owner) that can be granted exclusive access to\n * specific functions.\n *\n * By default, the owner account will be the one that deploys the contract. This\n * can later be changed with {transferOwnership}.\n *\n * This module is used through inheritance. It will make available the modifier\n * `onlyOwner`, which can be applied to your functions to restrict their use to\n * the owner.\n */\nabstract contract Ownable is Context {\n    address private _owner;\n\n    event OwnershipTransferred(address indexed previousOwner, address indexed newOwner);\n\n    /**\n     * @dev Initializes the contract setting the deployer as the initial owner.\n     */\n    constructor() {\n        _transferOwnership(_msgSender());\n    }\n\n    /**\n     * @dev Throws if called by any account other than the owner.\n     */\n    modifier onlyOwner() {\n        _checkOwner();\n        _;\n    }\n\n    /**\n     * @dev Returns the address of the current owner.\n     */\n    function owner() public view virtual returns (address) {\n        return _owner;\n    }\n\n    /**\n     * @dev Throws if the sender is not the owner.\n     */\n    function _checkOwner() internal view virtual {\n        require(owner() == _msgSender(), \"Ownable: caller is not the owner\");\n    }\n\n    /**\n     * @dev Leaves the contract without owner. It will not be possible to call\n     * `onlyOwner` functions anymore. Can only be called by the current owner.\n     *\n     * NOTE: Renouncing ownership will leave the contract without an owner,\n     * thereby removing any functionality that is only available to the owner.\n     */\n    function renounceOwnership() public virtual onlyOwner {\n        _transferOwnership(address(0));\n    }\n\n    /**\n     * @dev Transfers ownership of the contract to a new account (`newOwner`).\n     * Can only be called by the current owner.\n     */\n    function transferOwnership(address newOwner) public virtual onlyOwner {\n        require(newOwner != address(0), \"Ownable: new owner is the zero address\");\n        _transferOwnership(newOwner);\n    }\n\n    /**\n     * @dev Transfers ownership of the contract to a new account (`newOwner`).\n     * Internal function without access restriction.\n     */\n    function _transferOwnership(address newOwner) internal virtual {\n        address oldOwner = _owner;\n        _owner = newOwner;\n        emit OwnershipTransferred(oldOwner, newOwner);\n    }\n}\n"
    },
    "erc721a/contracts/ERC721A.sol": {
      "content": "// SPDX-License-Identifier: MIT\n// ERC721A Contracts v4.2.3\n// Creator: Chiru Labs\n\npragma solidity ^0.8.4;\n\nimport './IERC721A.sol';\n\n/**\n * @dev Interface of ERC721 token receiver.\n */\ninterface ERC721A__IERC721Receiver {\n    function onERC721Received(\n        address operator,\n        address from,\n        uint256 tokenId,\n        bytes calldata data\n    ) external returns (bytes4);\n}\n\n/**\n * @title ERC721A\n *\n * @dev Implementation of the [ERC721](https://eips.ethereum.org/EIPS/eip-721)\n * Non-Fungible Token Standard, including the Metadata extension.\n * Optimized for lower gas during batch mints.\n *\n * Token IDs are minted in sequential order (e.g. 0, 1, 2, 3, ...)\n * starting from `_startTokenId()`.\n *\n * Assumptions:\n *\n * - An owner cannot have more than 2**64 - 1 (max value of uint64) of supply.\n * - The maximum token ID cannot exceed 2**256 - 1 (max value of uint256).\n */\ncontract ERC721A is IERC721A {\n    // Bypass for a `--via-ir` bug (https://github.com/chiru-labs/ERC721A/pull/364).\n    struct TokenApprovalRef {\n        address value;\n    }\n\n    // =============================================================\n    //                           CONSTANTS\n    // =============================================================\n\n    // Mask of an entry in packed address data.\n    uint256 private constant _BITMASK_ADDRESS_DATA_ENTRY = (1 << 64) - 1;\n\n    // The bit position of `numberMinted` in packed address data.\n    uint256 private constant _BITPOS_NUMBER_MINTED = 64;\n\n    // The bit position of `numberBurned` in packed address data.\n    uint256 private constant _BITPOS_NUMBER_BURNED = 128;\n\n    // The bit position of `aux` in packed address data.\n    uint256 private constant _BITPOS_AUX = 192;\n\n    // Mask of all 256 bits in packed address data except the 64 bits for `aux`.\n    uint256 private constant _BITMASK_AUX_COMPLEMENT = (1 << 192) - 1;\n\n    // The bit position of `startTimestamp` in packed ownership.\n    uint256 private constant _BITPOS_START_TIMESTAMP = 160;\n\n    // The bit mask of the `burned` bit in packed ownership.\n    uint256 private constant _BITMASK_BURNED = 1 << 224;\n\n    // The bit position of the `nextInitialized` bit in packed ownership.\n    uint256 private constant _BITPOS_NEXT_INITIALIZED = 225;\n\n    // The bit mask of the `nextInitialized` bit in packed ownership.\n    uint256 private constant _BITMASK_NEXT_INITIALIZED = 1 << 225;\n\n    // The bit position of `extraData` in packed ownership.\n    uint256 private constant _BITPOS_EXTRA_DATA = 232;\n\n    // Mask of all 256 bits in a packed ownership except the 24 bits for `extraData`.\n    uint256 private constant _BITMASK_EXTRA_DATA_COMPLEMENT = (1 << 232) - 1;\n\n    // The mask of the lower 160 bits for addresses.\n    uint256 private constant _BITMASK_ADDRESS = (1 << 160) - 1;\n\n    // The maximum `quantity` that can be minted with {_mintERC2309}.\n    // This limit is to prevent overflows on the address data entries.\n    // For a limit of 5000, a total of 3.689e15 calls to {_mintERC2309}\n    // is required to cause an overflow, which is unrealistic.\n    uint256 private constant _MAX_MINT_ERC2309_QUANTITY_LIMIT = 5000;\n\n    // The `Transfer` event signature is given by:\n    // `keccak256(bytes(\"Transfer(address,address,uint256)\"))`.\n    bytes32 private constant _TRANSFER_EVENT_SIGNATURE =\n        0xddf252ad1be2c89b69c2b068fc378daa952ba7f163c4a11628f55a4df523b3ef;\n\n    // =============================================================\n    //                            STORAGE\n    // =============================================================\n\n    // The next token ID to be minted.\n    uint256 private _currentIndex;\n\n    // The number of tokens burned.\n    uint256 private _burnCounter;\n\n    // Token name\n    string private _name;\n\n    // Token symbol\n    string private _symbol;\n\n    // Mapping from token ID to ownership details\n    // An empty struct value does not necessarily mean the token is unowned.\n    // See {_packedOwnershipOf} implementation for details.\n    //\n    // Bits Layout:\n    // - [0..159]   `addr`\n    // - [160..223] `startTimestamp`\n    // - [224]      `burned`\n    // - [225]      `nextInitialized`\n    // - [232..255] `extraData`\n    mapping(uint256 => uint256) private _packedOwnerships;\n\n    // Mapping owner address to address data.\n    //\n    // Bits Layout:\n    // - [0..63]    `balance`\n    // - [64..127]  `numberMinted`\n    // - [128..191] `numberBurned`\n    // - [192..255] `aux`\n    mapping(address => uint256) private _packedAddressData;\n\n    // Mapping from token ID to approved address.\n    mapping(uint256 => TokenApprovalRef) private _tokenApprovals;\n\n    // Mapping from owner to operator approvals\n    mapping(address => mapping(address => bool)) private _operatorApprovals;\n\n    // =============================================================\n    //                          CONSTRUCTOR\n    // =============================================================\n\n    constructor(string memory name_, string memory symbol_) {\n        _name = name_;\n        _symbol = symbol_;\n        _currentIndex = _startTokenId();\n    }\n\n    // =============================================================\n    //                   TOKEN COUNTING OPERATIONS\n    // =============================================================\n\n    /**\n     * @dev Returns the starting token ID.\n     * To change the starting token ID, please override this function.\n     */\n    function _startTokenId() internal view virtual returns (uint256) {\n        return 0;\n    }\n\n    /**\n     * @dev Returns the next token ID to be minted.\n     */\n    function _nextTokenId() internal view virtual returns (uint256) {\n        return _currentIndex;\n    }\n\n    /**\n     * @dev Returns the total number of tokens in existence.\n     * Burned tokens will reduce the count.\n     * To get the total number of tokens minted, please see {_totalMinted}.\n     */\n    function totalSupply() public view virtual override returns (uint256) {\n        // Counter underflow is impossible as _burnCounter cannot be incremented\n        // more than `_currentIndex - _startTokenId()` times.\n        unchecked {\n            return _currentIndex - _burnCounter - _startTokenId();\n        }\n    }\n\n    /**\n     * @dev Returns the total amount of tokens minted in the contract.\n     */\n    function _totalMinted() internal view virtual returns (uint256) {\n        // Counter underflow is impossible as `_currentIndex` does not decrement,\n        // and it is initialized to `_startTokenId()`.\n        unchecked {\n            return _currentIndex - _startTokenId();\n        }\n    }\n\n    /**\n     * @dev Returns the total number of tokens burned.\n     */\n    function _totalBurned() internal view virtual returns (uint256) {\n        return _burnCounter;\n    }\n\n    // =============================================================\n    //                    ADDRESS DATA OPERATIONS\n    // =============================================================\n\n    /**\n     * @dev Returns the number of tokens in `owner`'s account.\n     */\n    function balanceOf(address owner) public view virtual override returns (uint256) {\n        if (owner == address(0)) revert BalanceQueryForZeroAddress();\n        return _packedAddressData[owner] & _BITMASK_ADDRESS_DATA_ENTRY;\n    }\n\n    /**\n     * Returns the number of tokens minted by `owner`.\n     */\n    function _numberMinted(address owner) internal view returns (uint256) {\n        return (_packedAddressData[owner] >> _BITPOS_NUMBER_MINTED) & _BITMASK_ADDRESS_DATA_ENTRY;\n    }\n\n    /**\n     * Returns the number of tokens burned by or on behalf of `owner`.\n     */\n    function _numberBurned(address owner) internal view returns (uint256) {\n        return (_packedAddressData[owner] >> _BITPOS_NUMBER_BURNED) & _BITMASK_ADDRESS_DATA_ENTRY;\n    }\n\n    /**\n     * Returns the auxiliary data for `owner`. (e.g. number of whitelist mint slots used).\n     */\n    function _getAux(address owner) internal view returns (uint64) {\n        return uint64(_packedAddressData[owner] >> _BITPOS_AUX);\n    }\n\n    /**\n     * Sets the auxiliary data for `owner`. (e.g. number of whitelist mint slots used).\n     * If there are multiple variables, please pack them into a uint64.\n     */\n    function _setAux(address owner, uint64 aux) internal virtual {\n        uint256 packed = _packedAddressData[owner];\n        uint256 auxCasted;\n        // Cast `aux` with assembly to avoid redundant masking.\n        assembly {\n            auxCasted := aux\n        }\n        packed = (packed & _BITMASK_AUX_COMPLEMENT) | (auxCasted << _BITPOS_AUX);\n        _packedAddressData[owner] = packed;\n    }\n\n    // =============================================================\n    //                            IERC165\n    // =============================================================\n\n    /**\n     * @dev Returns true if this contract implements the interface defined by\n     * `interfaceId`. See the corresponding\n     * [EIP section](https://eips.ethereum.org/EIPS/eip-165#how-interfaces-are-identified)\n     * to learn more about how these ids are created.\n     *\n     * This function call must use less than 30000 gas.\n     */\n    function supportsInterface(bytes4 interfaceId) public view virtual override returns (bool) {\n        // The interface IDs are constants representing the first 4 bytes\n        // of the XOR of all function selectors in the interface.\n        // See: [ERC165](https://eips.ethereum.org/EIPS/eip-165)\n        // (e.g. `bytes4(i.functionA.selector ^ i.functionB.selector ^ ...)`)\n        return\n            interfaceId == 0x01ffc9a7 || // ERC165 interface ID for ERC165.\n            interfaceId == 0x80ac58cd || // ERC165 interface ID for ERC721.\n            interfaceId == 0x5b5e139f; // ERC165 interface ID for ERC721Metadata.\n    }\n\n    // =============================================================\n    //                        IERC721Metadata\n    // =============================================================\n\n    /**\n     * @dev Returns the token collection name.\n     */\n    function name() public view virtual override returns (string memory) {\n        return _name;\n    }\n\n    /**\n     * @dev Returns the token collection symbol.\n     */\n    function symbol() public view virtual override returns (string memory) {\n        return _symbol;\n    }\n\n    /**\n     * @dev Returns the Uniform Resource Identifier (URI) for `tokenId` token.\n     */\n    function tokenURI(uint256 tokenId) public view virtual override returns (string memory) {\n        if (!_exists(tokenId)) revert URIQueryForNonexistentToken();\n\n        string memory baseURI = _baseURI();\n        return bytes(baseURI).length != 0 ? string(abi.encodePacked(baseURI, _toString(tokenId))) : '';\n    }\n\n    /**\n     * @dev Base URI for computing {tokenURI}. If set, the resulting URI for each\n     * token will be the concatenation of the `baseURI` and the `tokenId`. Empty\n     * by default, it can be overridden in child contracts.\n     */\n    function _baseURI() internal view virtual returns (string memory) {\n        return '';\n    }\n\n    // =============================================================\n    //                     OWNERSHIPS OPERATIONS\n    // =============================================================\n\n    /**\n     * @dev Returns the owner of the `tokenId` token.\n     *\n     * Requirements:\n     *\n     * - `tokenId` must exist.\n     */\n    function ownerOf(uint256 tokenId) public view virtual override returns (address) {\n        return address(uint160(_packedOwnershipOf(tokenId)));\n    }\n\n    /**\n     * @dev Gas spent here starts off proportional to the maximum mint batch size.\n     * It gradually moves to O(1) as tokens get transferred around over time.\n     */\n    function _ownershipOf(uint256 tokenId) internal view virtual returns (TokenOwnership memory) {\n        return _unpackedOwnership(_packedOwnershipOf(tokenId));\n    }\n\n    /**\n     * @dev Returns the unpacked `TokenOwnership` struct at `index`.\n     */\n    function _ownershipAt(uint256 index) internal view virtual returns (TokenOwnership memory) {\n        return _unpackedOwnership(_packedOwnerships[index]);\n    }\n\n    /**\n     * @dev Initializes the ownership slot minted at `index` for efficiency purposes.\n     */\n    function _initializeOwnershipAt(uint256 index) internal virtual {\n        if (_packedOwnerships[index] == 0) {\n            _packedOwnerships[index] = _packedOwnershipOf(index);\n        }\n    }\n\n    /**\n     * Returns the packed ownership data of `tokenId`.\n     */\n    function _packedOwnershipOf(uint256 tokenId) private view returns (uint256) {\n        uint256 curr = tokenId;\n\n        unchecked {\n            if (_startTokenId() <= curr)\n                if (curr < _currentIndex) {\n                    uint256 packed = _packedOwnerships[curr];\n                    // If not burned.\n                    if (packed & _BITMASK_BURNED == 0) {\n                        // Invariant:\n                        // There will always be an initialized ownership slot\n                        // (i.e. `ownership.addr != address(0) && ownership.burned == false`)\n                        // before an unintialized ownership slot\n                        // (i.e. `ownership.addr == address(0) && ownership.burned == false`)\n                        // Hence, `curr` will not underflow.\n                        //\n                        // We can directly compare the packed value.\n                        // If the address is zero, packed will be zero.\n                        while (packed == 0) {\n                            packed = _packedOwnerships[--curr];\n                        }\n                        return packed;\n                    }\n                }\n        }\n        revert OwnerQueryForNonexistentToken();\n    }\n\n    /**\n     * @dev Returns the unpacked `TokenOwnership` struct from `packed`.\n     */\n    function _unpackedOwnership(uint256 packed) private pure returns (TokenOwnership memory ownership) {\n        ownership.addr = address(uint160(packed));\n        ownership.startTimestamp = uint64(packed >> _BITPOS_START_TIMESTAMP);\n        ownership.burned = packed & _BITMASK_BURNED != 0;\n        ownership.extraData = uint24(packed >> _BITPOS_EXTRA_DATA);\n    }\n\n    /**\n     * @dev Packs ownership data into a single uint256.\n     */\n    function _packOwnershipData(address owner, uint256 flags) private view returns (uint256 result) {\n        assembly {\n            // Mask `owner` to the lower 160 bits, in case the upper bits somehow aren't clean.\n            owner := and(owner, _BITMASK_ADDRESS)\n            // `owner | (block.timestamp << _BITPOS_START_TIMESTAMP) | flags`.\n            result := or(owner, or(shl(_BITPOS_START_TIMESTAMP, timestamp()), flags))\n        }\n    }\n\n    /**\n     * @dev Returns the `nextInitialized` flag set if `quantity` equals 1.\n     */\n    function _nextInitializedFlag(uint256 quantity) private pure returns (uint256 result) {\n        // For branchless setting of the `nextInitialized` flag.\n        assembly {\n            // `(quantity == 1) << _BITPOS_NEXT_INITIALIZED`.\n            result := shl(_BITPOS_NEXT_INITIALIZED, eq(quantity, 1))\n        }\n    }\n\n    // =============================================================\n    //                      APPROVAL OPERATIONS\n    // =============================================================\n\n    /**\n     * @dev Gives permission to `to` to transfer `tokenId` token to another account.\n     * The approval is cleared when the token is transferred.\n     *\n     * Only a single account can be approved at a time, so approving the\n     * zero address clears previous approvals.\n     *\n     * Requirements:\n     *\n     * - The caller must own the token or be an approved operator.\n     * - `tokenId` must exist.\n     *\n     * Emits an {Approval} event.\n     */\n    function approve(address to, uint256 tokenId) public payable virtual override {\n        address owner = ownerOf(tokenId);\n\n        if (_msgSenderERC721A() != owner)\n            if (!isApprovedForAll(owner, _msgSenderERC721A())) {\n                revert ApprovalCallerNotOwnerNorApproved();\n            }\n\n        _tokenApprovals[tokenId].value = to;\n        emit Approval(owner, to, tokenId);\n    }\n\n    /**\n     * @dev Returns the account approved for `tokenId` token.\n     *\n     * Requirements:\n     *\n     * - `tokenId` must exist.\n     */\n    function getApproved(uint256 tokenId) public view virtual override returns (address) {\n        if (!_exists(tokenId)) revert ApprovalQueryForNonexistentToken();\n\n        return _tokenApprovals[tokenId].value;\n    }\n\n    /**\n     * @dev Approve or remove `operator` as an operator for the caller.\n     * Operators can call {transferFrom} or {safeTransferFrom}\n     * for any token owned by the caller.\n     *\n     * Requirements:\n     *\n     * - The `operator` cannot be the caller.\n     *\n     * Emits an {ApprovalForAll} event.\n     */\n    function setApprovalForAll(address operator, bool approved) public virtual override {\n        _operatorApprovals[_msgSenderERC721A()][operator] = approved;\n        emit ApprovalForAll(_msgSenderERC721A(), operator, approved);\n    }\n\n    /**\n     * @dev Returns if the `operator` is allowed to manage all of the assets of `owner`.\n     *\n     * See {setApprovalForAll}.\n     */\n    function isApprovedForAll(address owner, address operator) public view virtual override returns (bool) {\n        return _operatorApprovals[owner][operator];\n    }\n\n    /**\n     * @dev Returns whether `tokenId` exists.\n     *\n     * Tokens can be managed by their owner or approved accounts via {approve} or {setApprovalForAll}.\n     *\n     * Tokens start existing when they are minted. See {_mint}.\n     */\n    function _exists(uint256 tokenId) internal view virtual returns (bool) {\n        return\n            _startTokenId() <= tokenId &&\n            tokenId < _currentIndex && // If within bounds,\n            _packedOwnerships[tokenId] & _BITMASK_BURNED == 0; // and not burned.\n    }\n\n    /**\n     * @dev Returns whether `msgSender` is equal to `approvedAddress` or `owner`.\n     */\n    function _isSenderApprovedOrOwner(\n        address approvedAddress,\n        address owner,\n        address msgSender\n    ) private pure returns (bool result) {\n        assembly {\n            // Mask `owner` to the lower 160 bits, in case the upper bits somehow aren't clean.\n            owner := and(owner, _BITMASK_ADDRESS)\n            // Mask `msgSender` to the lower 160 bits, in case the upper bits somehow aren't clean.\n            msgSender := and(msgSender, _BITMASK_ADDRESS)\n            // `msgSender == owner || msgSender == approvedAddress`.\n            result := or(eq(msgSender, owner), eq(msgSender, approvedAddress))\n        }\n    }\n\n    /**\n     * @dev Returns the storage slot and value for the approved address of `tokenId`.\n     */\n    function _getApprovedSlotAndAddress(uint256 tokenId)\n        private\n        view\n        returns (uint256 approvedAddressSlot, address approvedAddress)\n    {\n        TokenApprovalRef storage tokenApproval = _tokenApprovals[tokenId];\n        // The following is equivalent to `approvedAddress = _tokenApprovals[tokenId].value`.\n        assembly {\n            approvedAddressSlot := tokenApproval.slot\n            approvedAddress := sload(approvedAddressSlot)\n        }\n    }\n\n    // =============================================================\n    //                      TRANSFER OPERATIONS\n    // =============================================================\n\n    /**\n     * @dev Transfers `tokenId` from `from` to `to`.\n     *\n     * Requirements:\n     *\n     * - `from` cannot be the zero address.\n     * - `to` cannot be the zero address.\n     * - `tokenId` token must be owned by `from`.\n     * - If the caller is not `from`, it must be approved to move this token\n     * by either {approve} or {setApprovalForAll}.\n     *\n     * Emits a {Transfer} event.\n     */\n    function transferFrom(\n        address from,\n        address to,\n        uint256 tokenId\n    ) public payable virtual override {\n        uint256 prevOwnershipPacked = _packedOwnershipOf(tokenId);\n\n        if (address(uint160(prevOwnershipPacked)) != from) revert TransferFromIncorrectOwner();\n\n        (uint256 approvedAddressSlot, address approvedAddress) = _getApprovedSlotAndAddress(tokenId);\n\n        // The nested ifs save around 20+ gas over a compound boolean condition.\n        if (!_isSenderApprovedOrOwner(approvedAddress, from, _msgSenderERC721A()))\n            if (!isApprovedForAll(from, _msgSenderERC721A())) revert TransferCallerNotOwnerNorApproved();\n\n        if (to == address(0)) revert TransferToZeroAddress();\n\n        _beforeTokenTransfers(from, to, tokenId, 1);\n\n        // Clear approvals from the previous owner.\n        assembly {\n            if approvedAddress {\n                // This is equivalent to `delete _tokenApprovals[tokenId]`.\n                sstore(approvedAddressSlot, 0)\n            }\n        }\n\n        // Underflow of the sender's balance is impossible because we check for\n        // ownership above and the recipient's balance can't realistically overflow.\n        // Counter overflow is incredibly unrealistic as `tokenId` would have to be 2**256.\n        unchecked {\n            // We can directly increment and decrement the balances.\n            --_packedAddressData[from]; // Updates: `balance -= 1`.\n            ++_packedAddressData[to]; // Updates: `balance += 1`.\n\n            // Updates:\n            // - `address` to the next owner.\n            // - `startTimestamp` to the timestamp of transfering.\n            // - `burned` to `false`.\n            // - `nextInitialized` to `true`.\n            _packedOwnerships[tokenId] = _packOwnershipData(\n                to,\n                _BITMASK_NEXT_INITIALIZED | _nextExtraData(from, to, prevOwnershipPacked)\n            );\n\n            // If the next slot may not have been initialized (i.e. `nextInitialized == false`) .\n            if (prevOwnershipPacked & _BITMASK_NEXT_INITIALIZED == 0) {\n                uint256 nextTokenId = tokenId + 1;\n                // If the next slot's address is zero and not burned (i.e. packed value is zero).\n                if (_packedOwnerships[nextTokenId] == 0) {\n                    // If the next slot is within bounds.\n                    if (nextTokenId != _currentIndex) {\n                        // Initialize the next slot to maintain correctness for `ownerOf(tokenId + 1)`.\n                        _packedOwnerships[nextTokenId] = prevOwnershipPacked;\n                    }\n                }\n            }\n        }\n\n        emit Transfer(from, to, tokenId);\n        _afterTokenTransfers(from, to, tokenId, 1);\n    }\n\n    /**\n     * @dev Equivalent to `safeTransferFrom(from, to, tokenId, '')`.\n     */\n    function safeTransferFrom(\n        address from,\n        address to,\n        uint256 tokenId\n    ) public payable virtual override {\n        safeTransferFrom(from, to, tokenId, '');\n    }\n\n    /**\n     * @dev Safely transfers `tokenId` token from `from` to `to`.\n     *\n     * Requirements:\n     *\n     * - `from` cannot be the zero address.\n     * - `to` cannot be the zero address.\n     * - `tokenId` token must exist and be owned by `from`.\n     * - If the caller is not `from`, it must be approved to move this token\n     * by either {approve} or {setApprovalForAll}.\n     * - If `to` refers to a smart contract, it must implement\n     * {IERC721Receiver-onERC721Received}, which is called upon a safe transfer.\n     *\n     * Emits a {Transfer} event.\n     */\n    function safeTransferFrom(\n        address from,\n        address to,\n        uint256 tokenId,\n        bytes memory _data\n    ) public payable virtual override {\n        transferFrom(from, to, tokenId);\n        if (to.code.length != 0)\n            if (!_checkContractOnERC721Received(from, to, tokenId, _data)) {\n                revert TransferToNonERC721ReceiverImplementer();\n            }\n    }\n\n    /**\n     * @dev Hook that is called before a set of serially-ordered token IDs\n     * are about to be transferred. This includes minting.\n     * And also called before burning one token.\n     *\n     * `startTokenId` - the first token ID to be transferred.\n     * `quantity` - the amount to be transferred.\n     *\n     * Calling conditions:\n     *\n     * - When `from` and `to` are both non-zero, `from`'s `tokenId` will be\n     * transferred to `to`.\n     * - When `from` is zero, `tokenId` will be minted for `to`.\n     * - When `to` is zero, `tokenId` will be burned by `from`.\n     * - `from` and `to` are never both zero.\n     */\n    function _beforeTokenTransfers(\n        address from,\n        address to,\n        uint256 startTokenId,\n        uint256 quantity\n    ) internal virtual {}\n\n    /**\n     * @dev Hook that is called after a set of serially-ordered token IDs\n     * have been transferred. This includes minting.\n     * And also called after one token has been burned.\n     *\n     * `startTokenId` - the first token ID to be transferred.\n     * `quantity` - the amount to be transferred.\n     *\n     * Calling conditions:\n     *\n     * - When `from` and `to` are both non-zero, `from`'s `tokenId` has been\n     * transferred to `to`.\n     * - When `from` is zero, `tokenId` has been minted for `to`.\n     * - When `to` is zero, `tokenId` has been burned by `from`.\n     * - `from` and `to` are never both zero.\n     */\n    function _afterTokenTransfers(\n        address from,\n        address to,\n        uint256 startTokenId,\n        uint256 quantity\n    ) internal virtual {}\n\n    /**\n     * @dev Private function to invoke {IERC721Receiver-onERC721Received} on a target contract.\n     *\n     * `from` - Previous owner of the given token ID.\n     * `to` - Target address that will receive the token.\n     * `tokenId` - Token ID to be transferred.\n     * `_data` - Optional data to send along with the call.\n     *\n     * Returns whether the call correctly returned the expected magic value.\n     */\n    function _checkContractOnERC721Received(\n        address from,\n        address to,\n        uint256 tokenId,\n        bytes memory _data\n    ) private returns (bool) {\n        try ERC721A__IERC721Receiver(to).onERC721Received(_msgSenderERC721A(), from, tokenId, _data) returns (\n            bytes4 retval\n        ) {\n            return retval == ERC721A__IERC721Receiver(to).onERC721Received.selector;\n        } catch (bytes memory reason) {\n            if (reason.length == 0) {\n                revert TransferToNonERC721ReceiverImplementer();\n            } else {\n                assembly {\n                    revert(add(32, reason), mload(reason))\n                }\n            }\n        }\n    }\n\n    // =============================================================\n    //                        MINT OPERATIONS\n    // =============================================================\n\n    /**\n     * @dev Mints `quantity` tokens and transfers them to `to`.\n     *\n     * Requirements:\n     *\n     * - `to` cannot be the zero address.\n     * - `quantity` must be greater than 0.\n     *\n     * Emits a {Transfer} event for each mint.\n     */\n    function _mint(address to, uint256 quantity) internal virtual {\n        uint256 startTokenId = _currentIndex;\n        if (quantity == 0) revert MintZeroQuantity();\n\n        _beforeTokenTransfers(address(0), to, startTokenId, quantity);\n\n        // Overflows are incredibly unrealistic.\n        // `balance` and `numberMinted` have a maximum limit of 2**64.\n        // `tokenId` has a maximum limit of 2**256.\n        unchecked {\n            // Updates:\n            // - `balance += quantity`.\n            // - `numberMinted += quantity`.\n            //\n            // We can directly add to the `balance` and `numberMinted`.\n            _packedAddressData[to] += quantity * ((1 << _BITPOS_NUMBER_MINTED) | 1);\n\n            // Updates:\n            // - `address` to the owner.\n            // - `startTimestamp` to the timestamp of minting.\n            // - `burned` to `false`.\n            // - `nextInitialized` to `quantity == 1`.\n            _packedOwnerships[startTokenId] = _packOwnershipData(\n                to,\n                _nextInitializedFlag(quantity) | _nextExtraData(address(0), to, 0)\n            );\n\n            uint256 toMasked;\n            uint256 end = startTokenId + quantity;\n\n            // Use assembly to loop and emit the `Transfer` event for gas savings.\n            // The duplicated `log4` removes an extra check and reduces stack juggling.\n            // The assembly, together with the surrounding Solidity code, have been\n            // delicately arranged to nudge the compiler into producing optimized opcodes.\n            assembly {\n                // Mask `to` to the lower 160 bits, in case the upper bits somehow aren't clean.\n                toMasked := and(to, _BITMASK_ADDRESS)\n                // Emit the `Transfer` event.\n                log4(\n                    0, // Start of data (0, since no data).\n                    0, // End of data (0, since no data).\n                    _TRANSFER_EVENT_SIGNATURE, // Signature.\n                    0, // `address(0)`.\n                    toMasked, // `to`.\n                    startTokenId // `tokenId`.\n                )\n\n                // The `iszero(eq(,))` check ensures that large values of `quantity`\n                // that overflows uint256 will make the loop run out of gas.\n                // The compiler will optimize the `iszero` away for performance.\n                for {\n                    let tokenId := add(startTokenId, 1)\n                } iszero(eq(tokenId, end)) {\n                    tokenId := add(tokenId, 1)\n                } {\n                    // Emit the `Transfer` event. Similar to above.\n                    log4(0, 0, _TRANSFER_EVENT_SIGNATURE, 0, toMasked, tokenId)\n                }\n            }\n            if (toMasked == 0) revert MintToZeroAddress();\n\n            _currentIndex = end;\n        }\n        _afterTokenTransfers(address(0), to, startTokenId, quantity);\n    }\n\n    /**\n     * @dev Mints `quantity` tokens and transfers them to `to`.\n     *\n     * This function is intended for efficient minting only during contract creation.\n     *\n     * It emits only one {ConsecutiveTransfer} as defined in\n     * [ERC2309](https://eips.ethereum.org/EIPS/eip-2309),\n     * instead of a sequence of {Transfer} event(s).\n     *\n     * Calling this function outside of contract creation WILL make your contract\n     * non-compliant with the ERC721 standard.\n     * For full ERC721 compliance, substituting ERC721 {Transfer} event(s) with the ERC2309\n     * {ConsecutiveTransfer} event is only permissible during contract creation.\n     *\n     * Requirements:\n     *\n     * - `to` cannot be the zero address.\n     * - `quantity` must be greater than 0.\n     *\n     * Emits a {ConsecutiveTransfer} event.\n     */\n    function _mintERC2309(address to, uint256 quantity) internal virtual {\n        uint256 startTokenId = _currentIndex;\n        if (to == address(0)) revert MintToZeroAddress();\n        if (quantity == 0) revert MintZeroQuantity();\n        if (quantity > _MAX_MINT_ERC2309_QUANTITY_LIMIT) revert MintERC2309QuantityExceedsLimit();\n\n        _beforeTokenTransfers(address(0), to, startTokenId, quantity);\n\n        // Overflows are unrealistic due to the above check for `quantity` to be below the limit.\n        unchecked {\n            // Updates:\n            // - `balance += quantity`.\n            // - `numberMinted += quantity`.\n            //\n            // We can directly add to the `balance` and `numberMinted`.\n            _packedAddressData[to] += quantity * ((1 << _BITPOS_NUMBER_MINTED) | 1);\n\n            // Updates:\n            // - `address` to the owner.\n            // - `startTimestamp` to the timestamp of minting.\n            // - `burned` to `false`.\n            // - `nextInitialized` to `quantity == 1`.\n            _packedOwnerships[startTokenId] = _packOwnershipData(\n                to,\n                _nextInitializedFlag(quantity) | _nextExtraData(address(0), to, 0)\n            );\n\n            emit ConsecutiveTransfer(startTokenId, startTokenId + quantity - 1, address(0), to);\n\n            _currentIndex = startTokenId + quantity;\n        }\n        _afterTokenTransfers(address(0), to, startTokenId, quantity);\n    }\n\n    /**\n     * @dev Safely mints `quantity` tokens and transfers them to `to`.\n     *\n     * Requirements:\n     *\n     * - If `to` refers to a smart contract, it must implement\n     * {IERC721Receiver-onERC721Received}, which is called for each safe transfer.\n     * - `quantity` must be greater than 0.\n     *\n     * See {_mint}.\n     *\n     * Emits a {Transfer} event for each mint.\n     */\n    function _safeMint(\n        address to,\n        uint256 quantity,\n        bytes memory _data\n    ) internal virtual {\n        _mint(to, quantity);\n\n        unchecked {\n            if (to.code.length != 0) {\n                uint256 end = _currentIndex;\n                uint256 index = end - quantity;\n                do {\n                    if (!_checkContractOnERC721Received(address(0), to, index++, _data)) {\n                        revert TransferToNonERC721ReceiverImplementer();\n                    }\n                } while (index < end);\n                // Reentrancy protection.\n                if (_currentIndex != end) revert();\n            }\n        }\n    }\n\n    /**\n     * @dev Equivalent to `_safeMint(to, quantity, '')`.\n     */\n    function _safeMint(address to, uint256 quantity) internal virtual {\n        _safeMint(to, quantity, '');\n    }\n\n    // =============================================================\n    //                        BURN OPERATIONS\n    // =============================================================\n\n    /**\n     * @dev Equivalent to `_burn(tokenId, false)`.\n     */\n    function _burn(uint256 tokenId) internal virtual {\n        _burn(tokenId, false);\n    }\n\n    /**\n     * @dev Destroys `tokenId`.\n     * The approval is cleared when the token is burned.\n     *\n     * Requirements:\n     *\n     * - `tokenId` must exist.\n     *\n     * Emits a {Transfer} event.\n     */\n    function _burn(uint256 tokenId, bool approvalCheck) internal virtual {\n        uint256 prevOwnershipPacked = _packedOwnershipOf(tokenId);\n\n        address from = address(uint160(prevOwnershipPacked));\n\n        (uint256 approvedAddressSlot, address approvedAddress) = _getApprovedSlotAndAddress(tokenId);\n\n        if (approvalCheck) {\n            // The nested ifs save around 20+ gas over a compound boolean condition.\n            if (!_isSenderApprovedOrOwner(approvedAddress, from, _msgSenderERC721A()))\n                if (!isApprovedForAll(from, _msgSenderERC721A())) revert TransferCallerNotOwnerNorApproved();\n        }\n\n        _beforeTokenTransfers(from, address(0), tokenId, 1);\n\n        // Clear approvals from the previous owner.\n        assembly {\n            if approvedAddress {\n                // This is equivalent to `delete _tokenApprovals[tokenId]`.\n                sstore(approvedAddressSlot, 0)\n            }\n        }\n\n        // Underflow of the sender's balance is impossible because we check for\n        // ownership above and the recipient's balance can't realistically overflow.\n        // Counter overflow is incredibly unrealistic as `tokenId` would have to be 2**256.\n        unchecked {\n            // Updates:\n            // - `balance -= 1`.\n            // - `numberBurned += 1`.\n            //\n            // We can directly decrement the balance, and increment the number burned.\n            // This is equivalent to `packed -= 1; packed += 1 << _BITPOS_NUMBER_BURNED;`.\n            _packedAddressData[from] += (1 << _BITPOS_NUMBER_BURNED) - 1;\n\n            // Updates:\n            // - `address` to the last owner.\n            // - `startTimestamp` to the timestamp of burning.\n            // - `burned` to `true`.\n            // - `nextInitialized` to `true`.\n            _packedOwnerships[tokenId] = _packOwnershipData(\n                from,\n                (_BITMASK_BURNED | _BITMASK_NEXT_INITIALIZED) | _nextExtraData(from, address(0), prevOwnershipPacked)\n            );\n\n            // If the next slot may not have been initialized (i.e. `nextInitialized == false`) .\n            if (prevOwnershipPacked & _BITMASK_NEXT_INITIALIZED == 0) {\n                uint256 nextTokenId = tokenId + 1;\n                // If the next slot's address is zero and not burned (i.e. packed value is zero).\n                if (_packedOwnerships[nextTokenId] == 0) {\n                    // If the next slot is within bounds.\n                    if (nextTokenId != _currentIndex) {\n                        // Initialize the next slot to maintain correctness for `ownerOf(tokenId + 1)`.\n                        _packedOwnerships[nextTokenId] = prevOwnershipPacked;\n                    }\n                }\n            }\n        }\n\n        emit Transfer(from, address(0), tokenId);\n        _afterTokenTransfers(from, address(0), tokenId, 1);\n\n        // Overflow not possible, as _burnCounter cannot be exceed _currentIndex times.\n        unchecked {\n            _burnCounter++;\n        }\n    }\n\n    // =============================================================\n    //                     EXTRA DATA OPERATIONS\n    // =============================================================\n\n    /**\n     * @dev Directly sets the extra data for the ownership data `index`.\n     */\n    function _setExtraDataAt(uint256 index, uint24 extraData) internal virtual {\n        uint256 packed = _packedOwnerships[index];\n        if (packed == 0) revert OwnershipNotInitializedForExtraData();\n        uint256 extraDataCasted;\n        // Cast `extraData` with assembly to avoid redundant masking.\n        assembly {\n            extraDataCasted := extraData\n        }\n        packed = (packed & _BITMASK_EXTRA_DATA_COMPLEMENT) | (extraDataCasted << _BITPOS_EXTRA_DATA);\n        _packedOwnerships[index] = packed;\n    }\n\n    /**\n     * @dev Called during each token transfer to set the 24bit `extraData` field.\n     * Intended to be overridden by the cosumer contract.\n     *\n     * `previousExtraData` - the value of `extraData` before transfer.\n     *\n     * Calling conditions:\n     *\n     * - When `from` and `to` are both non-zero, `from`'s `tokenId` will be\n     * transferred to `to`.\n     * - When `from` is zero, `tokenId` will be minted for `to`.\n     * - When `to` is zero, `tokenId` will be burned by `from`.\n     * - `from` and `to` are never both zero.\n     */\n    function _extraData(\n        address from,\n        address to,\n        uint24 previousExtraData\n    ) internal view virtual returns (uint24) {}\n\n    /**\n     * @dev Returns the next extra data for the packed ownership data.\n     * The returned result is shifted into position.\n     */\n    function _nextExtraData(\n        address from,\n        address to,\n        uint256 prevOwnershipPacked\n    ) private view returns (uint256) {\n        uint24 extraData = uint24(prevOwnershipPacked >> _BITPOS_EXTRA_DATA);\n        return uint256(_extraData(from, to, extraData)) << _BITPOS_EXTRA_DATA;\n    }\n\n    // =============================================================\n    //                       OTHER OPERATIONS\n    // =============================================================\n\n    /**\n     * @dev Returns the message sender (defaults to `msg.sender`).\n     *\n     * If you are writing GSN compatible contracts, you need to override this function.\n     */\n    function _msgSenderERC721A() internal view virtual returns (address) {\n        return msg.sender;\n    }\n\n    /**\n     * @dev Converts a uint256 to its ASCII string decimal representation.\n     */\n    function _toString(uint256 value) internal pure virtual returns (string memory str) {\n        assembly {\n            // The maximum value of a uint256 contains 78 digits (1 byte per digit), but\n            // we allocate 0xa0 bytes to keep the free memory pointer 32-byte word aligned.\n            // We will need 1 word for the trailing zeros padding, 1 word for the length,\n            // and 3 words for a maximum of 78 digits. Total: 5 * 0x20 = 0xa0.\n            let m := add(mload(0x40), 0xa0)\n            // Update the free memory pointer to allocate.\n            mstore(0x40, m)\n            // Assign the `str` to the end.\n            str := sub(m, 0x20)\n            // Zeroize the slot after the string.\n            mstore(str, 0)\n\n            // Cache the end of the memory to calculate the length later.\n            let end := str\n\n            // We write the string from rightmost digit to leftmost digit.\n            // The following is essentially a do-while loop that also handles the zero case.\n            // prettier-ignore\n            for { let temp := value } 1 {} {\n                str := sub(str, 1)\n                // Write the character to the pointer.\n                // The ASCII index of the '0' character is 48.\n                mstore8(str, add(48, mod(temp, 10)))\n                // Keep dividing `temp` until zero.\n                temp := div(temp, 10)\n                // prettier-ignore\n                if iszero(temp) { break }\n            }\n\n            let length := sub(end, str)\n            // Move the pointer 32 bytes leftwards to make room for the length.\n            str := sub(str, 0x20)\n            // Store the length.\n            mstore(str, length)\n        }\n    }\n}\n"
    },
    "erc721a/contracts/IERC721A.sol": {
      "content": "// SPDX-License-Identifier: MIT\n// ERC721A Contracts v4.2.3\n// Creator: Chiru Labs\n\npragma solidity ^0.8.4;\n\n/**\n * @dev Interface of ERC721A.\n */\ninterface IERC721A {\n    /**\n     * The caller must own the token or be an approved operator.\n     */\n    error ApprovalCallerNotOwnerNorApproved();\n\n    /**\n     * The token does not exist.\n     */\n    error ApprovalQueryForNonexistentToken();\n\n    /**\n     * Cannot query the balance for the zero address.\n     */\n    error BalanceQueryForZeroAddress();\n\n    /**\n     * Cannot mint to the zero address.\n     */\n    error MintToZeroAddress();\n\n    /**\n     * The quantity of tokens minted must be more than zero.\n     */\n    error MintZeroQuantity();\n\n    /**\n     * The token does not exist.\n     */\n    error OwnerQueryForNonexistentToken();\n\n    /**\n     * The caller must own the token or be an approved operator.\n     */\n    error TransferCallerNotOwnerNorApproved();\n\n    /**\n     * The token must be owned by `from`.\n     */\n    error TransferFromIncorrectOwner();\n\n    /**\n     * Cannot safely transfer to a contract that does not implement the\n     * ERC721Receiver interface.\n     */\n    error TransferToNonERC721ReceiverImplementer();\n\n    /**\n     * Cannot transfer to the zero address.\n     */\n    error TransferToZeroAddress();\n\n    /**\n     * The token does not exist.\n     */\n    error URIQueryForNonexistentToken();\n\n    /**\n     * The `quantity` minted with ERC2309 exceeds the safety limit.\n     */\n    error MintERC2309QuantityExceedsLimit();\n\n    /**\n     * The `extraData` cannot be set on an unintialized ownership slot.\n     */\n    error OwnershipNotInitializedForExtraData();\n\n    // =============================================================\n    //                            STRUCTS\n    // =============================================================\n\n    struct TokenOwnership {\n        // The address of the owner.\n        address addr;\n        // Stores the start time of ownership with minimal overhead for tokenomics.\n        uint64 startTimestamp;\n        // Whether the token has been burned.\n        bool burned;\n        // Arbitrary data similar to `startTimestamp` that can be set via {_extraData}.\n        uint24 extraData;\n    }\n\n    // =============================================================\n    //                         TOKEN COUNTERS\n    // =============================================================\n\n    /**\n     * @dev Returns the total number of tokens in existence.\n     * Burned tokens will reduce the count.\n     * To get the total number of tokens minted, please see {_totalMinted}.\n     */\n    function totalSupply() external view returns (uint256);\n\n    // =============================================================\n    //                            IERC165\n    // =============================================================\n\n    /**\n     * @dev Returns true if this contract implements the interface defined by\n     * `interfaceId`. See the corresponding\n     * [EIP section](https://eips.ethereum.org/EIPS/eip-165#how-interfaces-are-identified)\n     * to learn more about how these ids are created.\n     *\n     * This function call must use less than 30000 gas.\n     */\n    function supportsInterface(bytes4 interfaceId) external view returns (bool);\n\n    // =============================================================\n    //                            IERC721\n    // =============================================================\n\n    /**\n     * @dev Emitted when `tokenId` token is transferred from `from` to `to`.\n     */\n    event Transfer(address indexed from, address indexed to, uint256 indexed tokenId);\n\n    /**\n     * @dev Emitted when `owner` enables `approved` to manage the `tokenId` token.\n     */\n    event Approval(address indexed owner, address indexed approved, uint256 indexed tokenId);\n\n    /**\n     * @dev Emitted when `owner` enables or disables\n     * (`approved`) `operator` to manage all of its assets.\n     */\n    event ApprovalForAll(address indexed owner, address indexed operator, bool approved);\n\n    /**\n     * @dev Returns the number of tokens in `owner`'s account.\n     */\n    function balanceOf(address owner) external view returns (uint256 balance);\n\n    /**\n     * @dev Returns the owner of the `tokenId` token.\n     *\n     * Requirements:\n     *\n     * - `tokenId` must exist.\n     */\n    function ownerOf(uint256 tokenId) external view returns (address owner);\n\n    /**\n     * @dev Safely transfers `tokenId` token from `from` to `to`,\n     * checking first that contract recipients are aware of the ERC721 protocol\n     * to prevent tokens from being forever locked.\n     *\n     * Requirements:\n     *\n     * - `from` cannot be the zero address.\n     * - `to` cannot be the zero address.\n     * - `tokenId` token must exist and be owned by `from`.\n     * - If the caller is not `from`, it must be have been allowed to move\n     * this token by either {approve} or {setApprovalForAll}.\n     * - If `to` refers to a smart contract, it must implement\n     * {IERC721Receiver-onERC721Received}, which is called upon a safe transfer.\n     *\n     * Emits a {Transfer} event.\n     */\n    function safeTransferFrom(\n        address from,\n        address to,\n        uint256 tokenId,\n        bytes calldata data\n    ) external payable;\n\n    /**\n     * @dev Equivalent to `safeTransferFrom(from, to, tokenId, '')`.\n     */\n    function safeTransferFrom(\n        address from,\n        address to,\n        uint256 tokenId\n    ) external payable;\n\n    /**\n     * @dev Transfers `tokenId` from `from` to `to`.\n     *\n     * WARNING: Usage of this method is discouraged, use {safeTransferFrom}\n     * whenever possible.\n     *\n     * Requirements:\n     *\n     * - `from` cannot be the zero address.\n     * - `to` cannot be the zero address.\n     * - `tokenId` token must be owned by `from`.\n     * - If the caller is not `from`, it must be approved to move this token\n     * by either {approve} or {setApprovalForAll}.\n     *\n     * Emits a {Transfer} event.\n     */\n    function transferFrom(\n        address from,\n        address to,\n        uint256 tokenId\n    ) external payable;\n\n    /**\n     * @dev Gives permission to `to` to transfer `tokenId` token to another account.\n     * The approval is cleared when the token is transferred.\n     *\n     * Only a single account can be approved at a time, so approving the\n     * zero address clears previous approvals.\n     *\n     * Requirements:\n     *\n     * - The caller must own the token or be an approved operator.\n     * - `tokenId` must exist.\n     *\n     * Emits an {Approval} event.\n     */\n    function approve(address to, uint256 tokenId) external payable;\n\n    /**\n     * @dev Approve or remove `operator` as an operator for the caller.\n     * Operators can call {transferFrom} or {safeTransferFrom}\n     * for any token owned by the caller.\n     *\n     * Requirements:\n     *\n     * - The `operator` cannot be the caller.\n     *\n     * Emits an {ApprovalForAll} event.\n     */\n    function setApprovalForAll(address operator, bool _approved) external;\n\n    /**\n     * @dev Returns the account approved for `tokenId` token.\n     *\n     * Requirements:\n     *\n     * - `tokenId` must exist.\n     */\n    function getApproved(uint256 tokenId) external view returns (address operator);\n\n    /**\n     * @dev Returns if the `operator` is allowed to manage all of the assets of `owner`.\n     *\n     * See {setApprovalForAll}.\n     */\n    function isApprovedForAll(address owner, address operator) external view returns (bool);\n\n    // =============================================================\n    //                        IERC721Metadata\n    // =============================================================\n\n    /**\n     * @dev Returns the token collection name.\n     */\n    function name() external view returns (string memory);\n\n    /**\n     * @dev Returns the token collection symbol.\n     */\n    function symbol() external view returns (string memory);\n\n    /**\n     * @dev Returns the Uniform Resource Identifier (URI) for `tokenId` token.\n     */\n    function tokenURI(uint256 tokenId) external view returns (string memory);\n\n    // =============================================================\n    //                           IERC2309\n    // =============================================================\n\n    /**\n     * @dev Emitted when tokens in `fromTokenId` to `toTokenId`\n     * (inclusive) is transferred from `from` to `to`, as defined in the\n     * [ERC2309](https://eips.ethereum.org/EIPS/eip-2309) standard.\n     *\n     * See {_mintERC2309} for more details.\n     */\n    event ConsecutiveTransfer(uint256 indexed fromTokenId, uint256 toTokenId, address indexed from, address indexed to);\n}\n"
    },
    "@openzeppelin/contracts/utils/math/Math.sol": {
      "content": "// SPDX-License-Identifier: MIT\n// OpenZeppelin Contracts (last updated v4.8.0) (utils/math/Math.sol)\n\npragma solidity ^0.8.0;\n\n/**\n * @dev Standard math utilities missing in the Solidity language.\n */\nlibrary Math {\n    enum Rounding {\n        Down, // Toward negative infinity\n        Up, // Toward infinity\n        Zero // Toward zero\n    }\n\n    /**\n     * @dev Returns the largest of two numbers.\n     */\n    function max(uint256 a, uint256 b) internal pure returns (uint256) {\n        return a > b ? a : b;\n    }\n\n    /**\n     * @dev Returns the smallest of two numbers.\n     */\n    function min(uint256 a, uint256 b) internal pure returns (uint256) {\n        return a < b ? a : b;\n    }\n\n    /**\n     * @dev Returns the average of two numbers. The result is rounded towards\n     * zero.\n     */\n    function average(uint256 a, uint256 b) internal pure returns (uint256) {\n        // (a + b) / 2 can overflow.\n        return (a & b) + (a ^ b) / 2;\n    }\n\n    /**\n     * @dev Returns the ceiling of the division of two numbers.\n     *\n     * This differs from standard division with `/` in that it rounds up instead\n     * of rounding down.\n     */\n    function ceilDiv(uint256 a, uint256 b) internal pure returns (uint256) {\n        // (a + b - 1) / b can overflow on addition, so we distribute.\n        return a == 0 ? 0 : (a - 1) / b + 1;\n    }\n\n    /**\n     * @notice Calculates floor(x * y / denominator) with full precision. Throws if result overflows a uint256 or denominator == 0\n     * @dev Original credit to Remco Bloemen under MIT license (https://xn--2-umb.com/21/muldiv)\n     * with further edits by Uniswap Labs also under MIT license.\n     */\n    function mulDiv(\n        uint256 x,\n        uint256 y,\n        uint256 denominator\n    ) internal pure returns (uint256 result) {\n        unchecked {\n            // 512-bit multiply [prod1 prod0] = x * y. Compute the product mod 2^256 and mod 2^256 - 1, then use\n            // use the Chinese Remainder Theorem to reconstruct the 512 bit result. The result is stored in two 256\n            // variables such that product = prod1 * 2^256 + prod0.\n            uint256 prod0; // Least significant 256 bits of the product\n            uint256 prod1; // Most significant 256 bits of the product\n            assembly {\n                let mm := mulmod(x, y, not(0))\n                prod0 := mul(x, y)\n                prod1 := sub(sub(mm, prod0), lt(mm, prod0))\n            }\n\n            // Handle non-overflow cases, 256 by 256 division.\n            if (prod1 == 0) {\n                return prod0 / denominator;\n            }\n\n            // Make sure the result is less than 2^256. Also prevents denominator == 0.\n            require(denominator > prod1);\n\n            ///////////////////////////////////////////////\n            // 512 by 256 division.\n            ///////////////////////////////////////////////\n\n            // Make division exact by subtracting the remainder from [prod1 prod0].\n            uint256 remainder;\n            assembly {\n                // Compute remainder using mulmod.\n                remainder := mulmod(x, y, denominator)\n\n                // Subtract 256 bit number from 512 bit number.\n                prod1 := sub(prod1, gt(remainder, prod0))\n                prod0 := sub(prod0, remainder)\n            }\n\n            // Factor powers of two out of denominator and compute largest power of two divisor of denominator. Always >= 1.\n            // See https://cs.stackexchange.com/q/138556/92363.\n\n            // Does not overflow because the denominator cannot be zero at this stage in the function.\n            uint256 twos = denominator & (~denominator + 1);\n            assembly {\n                // Divide denominator by twos.\n                denominator := div(denominator, twos)\n\n                // Divide [prod1 prod0] by twos.\n                prod0 := div(prod0, twos)\n\n                // Flip twos such that it is 2^256 / twos. If twos is zero, then it becomes one.\n                twos := add(div(sub(0, twos), twos), 1)\n            }\n\n            // Shift in bits from prod1 into prod0.\n            prod0 |= prod1 * twos;\n\n            // Invert denominator mod 2^256. Now that denominator is an odd number, it has an inverse modulo 2^256 such\n            // that denominator * inv = 1 mod 2^256. Compute the inverse by starting with a seed that is correct for\n            // four bits. That is, denominator * inv = 1 mod 2^4.\n            uint256 inverse = (3 * denominator) ^ 2;\n\n            // Use the Newton-Raphson iteration to improve the precision. Thanks to Hensel's lifting lemma, this also works\n            // in modular arithmetic, doubling the correct bits in each step.\n            inverse *= 2 - denominator * inverse; // inverse mod 2^8\n            inverse *= 2 - denominator * inverse; // inverse mod 2^16\n            inverse *= 2 - denominator * inverse; // inverse mod 2^32\n            inverse *= 2 - denominator * inverse; // inverse mod 2^64\n            inverse *= 2 - denominator * inverse; // inverse mod 2^128\n            inverse *= 2 - denominator * inverse; // inverse mod 2^256\n\n            // Because the division is now exact we can divide by multiplying with the modular inverse of denominator.\n            // This will give us the correct result modulo 2^256. Since the preconditions guarantee that the outcome is\n            // less than 2^256, this is the final result. We don't need to compute the high bits of the result and prod1\n            // is no longer required.\n            result = prod0 * inverse;\n            return result;\n        }\n    }\n\n    /**\n     * @notice Calculates x * y / denominator with full precision, following the selected rounding direction.\n     */\n    function mulDiv(\n        uint256 x,\n        uint256 y,\n        uint256 denominator,\n        Rounding rounding\n    ) internal pure returns (uint256) {\n        uint256 result = mulDiv(x, y, denominator);\n        if (rounding == Rounding.Up && mulmod(x, y, denominator) > 0) {\n            result += 1;\n        }\n        return result;\n    }\n\n    /**\n     * @dev Returns the square root of a number. If the number is not a perfect square, the value is rounded down.\n     *\n     * Inspired by Henry S. Warren, Jr.'s \"Hacker's Delight\" (Chapter 11).\n     */\n    function sqrt(uint256 a) internal pure returns (uint256) {\n        if (a == 0) {\n            return 0;\n        }\n\n        // For our first guess, we get the biggest power of 2 which is smaller than the square root of the target.\n        //\n        // We know that the \"msb\" (most significant bit) of our target number `a` is a power of 2 such that we have\n        // `msb(a) <= a < 2*msb(a)`. This value can be written `msb(a)=2**k` with `k=log2(a)`.\n        //\n        // This can be rewritten `2**log2(a) <= a < 2**(log2(a) + 1)`\n        // → `sqrt(2**k) <= sqrt(a) < sqrt(2**(k+1))`\n        // → `2**(k/2) <= sqrt(a) < 2**((k+1)/2) <= 2**(k/2 + 1)`\n        //\n        // Consequently, `2**(log2(a) / 2)` is a good first approximation of `sqrt(a)` with at least 1 correct bit.\n        uint256 result = 1 << (log2(a) >> 1);\n\n        // At this point `result` is an estimation with one bit of precision. We know the true value is a uint128,\n        // since it is the square root of a uint256. Newton's method converges quadratically (precision doubles at\n        // every iteration). We thus need at most 7 iteration to turn our partial result with one bit of precision\n        // into the expected uint128 result.\n        unchecked {\n            result = (result + a / result) >> 1;\n            result = (result + a / result) >> 1;\n            result = (result + a / result) >> 1;\n            result = (result + a / result) >> 1;\n            result = (result + a / result) >> 1;\n            result = (result + a / result) >> 1;\n            result = (result + a / result) >> 1;\n            return min(result, a / result);\n        }\n    }\n\n    /**\n     * @notice Calculates sqrt(a), following the selected rounding direction.\n     */\n    function sqrt(uint256 a, Rounding rounding) internal pure returns (uint256) {\n        unchecked {\n            uint256 result = sqrt(a);\n            return result + (rounding == Rounding.Up && result * result < a ? 1 : 0);\n        }\n    }\n\n    /**\n     * @dev Return the log in base 2, rounded down, of a positive value.\n     * Returns 0 if given 0.\n     */\n    function log2(uint256 value) internal pure returns (uint256) {\n        uint256 result = 0;\n        unchecked {\n            if (value >> 128 > 0) {\n                value >>= 128;\n                result += 128;\n            }\n            if (value >> 64 > 0) {\n                value >>= 64;\n                result += 64;\n            }\n            if (value >> 32 > 0) {\n                value >>= 32;\n                result += 32;\n            }\n            if (value >> 16 > 0) {\n                value >>= 16;\n                result += 16;\n            }\n            if (value >> 8 > 0) {\n                value >>= 8;\n                result += 8;\n            }\n            if (value >> 4 > 0) {\n                value >>= 4;\n                result += 4;\n            }\n            if (value >> 2 > 0) {\n                value >>= 2;\n                result += 2;\n            }\n            if (value >> 1 > 0) {\n                result += 1;\n            }\n        }\n        return result;\n    }\n\n    /**\n     * @dev Return the log in base 2, following the selected rounding direction, of a positive value.\n     * Returns 0 if given 0.\n     */\n    function log2(uint256 value, Rounding rounding) internal pure returns (uint256) {\n        unchecked {\n            uint256 result = log2(value);\n            return result + (rounding == Rounding.Up && 1 << result < value ? 1 : 0);\n        }\n    }\n\n    /**\n     * @dev Return the log in base 10, rounded down, of a positive value.\n     * Returns 0 if given 0.\n     */\n    function log10(uint256 value) internal pure returns (uint256) {\n        uint256 result = 0;\n        unchecked {\n            if (value >= 10**64) {\n                value /= 10**64;\n                result += 64;\n            }\n            if (value >= 10**32) {\n                value /= 10**32;\n                result += 32;\n            }\n            if (value >= 10**16) {\n                value /= 10**16;\n                result += 16;\n            }\n            if (value >= 10**8) {\n                value /= 10**8;\n                result += 8;\n            }\n            if (value >= 10**4) {\n                value /= 10**4;\n                result += 4;\n            }\n            if (value >= 10**2) {\n                value /= 10**2;\n                result += 2;\n            }\n            if (value >= 10**1) {\n                result += 1;\n            }\n        }\n        return result;\n    }\n\n    /**\n     * @dev Return the log in base 10, following the selected rounding direction, of a positive value.\n     * Returns 0 if given 0.\n     */\n    function log10(uint256 value, Rounding rounding) internal pure returns (uint256) {\n        unchecked {\n            uint256 result = log10(value);\n            return result + (rounding == Rounding.Up && 10**result < value ? 1 : 0);\n        }\n    }\n\n    /**\n     * @dev Return the log in base 256, rounded down, of a positive value.\n     * Returns 0 if given 0.\n     *\n     * Adding one to the result gives the number of pairs of hex symbols needed to represent `value` as a hex string.\n     */\n    function log256(uint256 value) internal pure returns (uint256) {\n        uint256 result = 0;\n        unchecked {\n            if (value >> 128 > 0) {\n                value >>= 128;\n                result += 16;\n            }\n            if (value >> 64 > 0) {\n                value >>= 64;\n                result += 8;\n            }\n            if (value >> 32 > 0) {\n                value >>= 32;\n                result += 4;\n            }\n            if (value >> 16 > 0) {\n                value >>= 16;\n                result += 2;\n            }\n            if (value >> 8 > 0) {\n                result += 1;\n            }\n        }\n        return result;\n    }\n\n    /**\n     * @dev Return the log in base 10, following the selected rounding direction, of a positive value.\n     * Returns 0 if given 0.\n     */\n    function log256(uint256 value, Rounding rounding) internal pure returns (uint256) {\n        unchecked {\n            uint256 result = log256(value);\n            return result + (rounding == Rounding.Up && 1 << (result * 8) < value ? 1 : 0);\n        }\n    }\n}\n"
    },
    "@openzeppelin/contracts/utils/Context.sol": {
      "content": "// SPDX-License-Identifier: MIT\n// OpenZeppelin Contracts v4.4.1 (utils/Context.sol)\n\npragma solidity ^0.8.0;\n\n/**\n * @dev Provides information about the current execution context, including the\n * sender of the transaction and its data. While these are generally available\n * via msg.sender and msg.data, they should not be accessed in such a direct\n * manner, since when dealing with meta-transactions the account sending and\n * paying for execution may not be the actual sender (as far as an application\n * is concerned).\n *\n * This contract is only required for intermediate, library-like contracts.\n */\nabstract contract Context {\n    function _msgSender() internal view virtual returns (address) {\n        return msg.sender;\n    }\n\n    function _msgData() internal view virtual returns (bytes calldata) {\n        return msg.data;\n    }\n}\n"
    }
  },
  "settings": {
    "optimizer": {
      "enabled": false,
      "runs": 200
    },
    "outputSelection": {
      "*": {
        "*": [
          "evm.bytecode",
          "evm.deployedBytecode",
          "devdoc",
          "userdoc",
          "metadata",
          "abi"
        ]
      }
    }
  }
}