// Sources flattened with tronbox v3.3.0 https://tronbox.io

// File: @openzeppelin/contracts/token/ERC20/IERC20.sol

// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts (last updated v4.9.0) (token/ERC20/IERC20.sol)

pragma solidity >=0.8.0 <0.9.0;

/**
 * @dev Interface of the ERC20 standard as defined in the EIP.
 */
interface IERC20 {
    /**
     * @dev Emitted when `value` tokens are moved from one account (`from`) to
     * another (`to`).
     *
     * Note that `value` may be zero.
     */
    event Transfer(address indexed from, address indexed to, uint256 value);

    /**
     * @dev Emitted when the allowance of a `spender` for an `owner` is set by
     * a call to {approve}. `value` is the new allowance.
     */
    event Approval(address indexed owner, address indexed spender, uint256 value);

    /**
     * @dev Returns the amount of tokens in existence.
     */
    function totalSupply() external view returns (uint256);

    /**
     * @dev Returns the amount of tokens owned by `account`.
     */
    function balanceOf(address account) external view returns (uint256);

    /**
     * @dev Moves `amount` tokens from the caller's account to `to`.
     *
     * Returns a boolean value indicating whether the operation succeeded.
     *
     * Emits a {Transfer} event.
     */
    function transfer(address to, uint256 amount) external returns (bool);

    /**
     * @dev Returns the remaining number of tokens that `spender` will be
     * allowed to spend on behalf of `owner` through {transferFrom}. This is
     * zero by default.
     *
     * This value changes when {approve} or {transferFrom} are called.
     */
    function allowance(address owner, address spender) external view returns (uint256);

    /**
     * @dev Sets `amount` as the allowance of `spender` over the caller's tokens.
     *
     * Returns a boolean value indicating whether the operation succeeded.
     *
     * IMPORTANT: Beware that changing an allowance with this method brings the risk
     * that someone may use both the old and the new allowance by unfortunate
     * transaction ordering. One possible solution to mitigate this race
     * condition is to first reduce the spender's allowance to 0 and set the
     * desired value afterwards:
     * https://github.com/ethereum/EIPs/issues/20#issuecomment-263524729
     *
     * Emits an {Approval} event.
     */
    function approve(address spender, uint256 amount) external returns (bool);

    /**
     * @dev Moves `amount` tokens from `from` to `to` using the
     * allowance mechanism. `amount` is then deducted from the caller's
     * allowance.
     *
     * Returns a boolean value indicating whether the operation succeeded.
     *
     * Emits a {Transfer} event.
     */
    function transferFrom(address from, address to, uint256 amount) external returns (bool);
}

// File: @openzeppelin/contracts/token/ERC20/extensions/IERC20Permit.sol

// OpenZeppelin Contracts (last updated v4.9.0) (token/ERC20/extensions/IERC20Permit.sol)


/**
 * @dev Interface of the ERC20 Permit extension allowing approvals to be made via signatures, as defined in
 * https://eips.ethereum.org/EIPS/eip-2612[EIP-2612].
 *
 * Adds the {permit} method, which can be used to change an account's ERC20 allowance (see {IERC20-allowance}) by
 * presenting a message signed by the account. By not relying on {IERC20-approve}, the token holder account doesn't
 * need to send a transaction, and thus is not required to hold Ether at all.
 */
interface IERC20Permit {
    /**
     * @dev Sets `value` as the allowance of `spender` over ``owner``'s tokens,
     * given ``owner``'s signed approval.
     *
     * IMPORTANT: The same issues {IERC20-approve} has related to transaction
     * ordering also apply here.
     *
     * Emits an {Approval} event.
     *
     * Requirements:
     *
     * - `spender` cannot be the zero address.
     * - `deadline` must be a timestamp in the future.
     * - `v`, `r` and `s` must be a valid `secp256k1` signature from `owner`
     * over the EIP712-formatted function arguments.
     * - the signature must use ``owner``'s current nonce (see {nonces}).
     *
     * For more information on the signature format, see the
     * https://eips.ethereum.org/EIPS/eip-2612#specification[relevant EIP
     * section].
     */
    function permit(
        address owner,
        address spender,
        uint256 value,
        uint256 deadline,
        uint8 v,
        bytes32 r,
        bytes32 s
    ) external;

    /**
     * @dev Returns the current nonce for `owner`. This value must be
     * included whenever a signature is generated for {permit}.
     *
     * Every successful call to {permit} increases ``owner``'s nonce by one. This
     * prevents a signature from being used multiple times.
     */
    function nonces(address owner) external view returns (uint256);

    /**
     * @dev Returns the domain separator used in the encoding of the signature for {permit}, as defined by {EIP712}.
     */
    // solhint-disable-next-line func-name-mixedcase
    function DOMAIN_SEPARATOR() external view returns (bytes32);
}

// File: @openzeppelin/contracts/utils/Address.sol

// OpenZeppelin Contracts (last updated v4.9.0) (utils/Address.sol)


/**
 * @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
     *
     * Furthermore, `isContract` will also return true if the target contract within
     * the same transaction is already scheduled for destruction by `SELFDESTRUCT`,
     * which only has an effect at the end of a transaction.
     * ====
     *
     * [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://consensys.net/diligence/blog/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/v0.8.0/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 functionCallWithValue(target, data, 0, "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");
        (bool success, bytes memory returndata) = target.call{value: value}(data);
        return verifyCallResultFromTarget(target, 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) {
        (bool success, bytes memory returndata) = target.staticcall(data);
        return verifyCallResultFromTarget(target, 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");
    }

    /**
     * @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) {
        (bool success, bytes memory returndata) = target.delegatecall(data);
        return verifyCallResultFromTarget(target, success, returndata, errorMessage);
    }

    /**
     * @dev Tool to verify that a low level call to smart-contract was successful, and revert (either by bubbling
     * the revert reason or using the provided one) in case of unsuccessful call or if target was not a contract.
     *
     * _Available since v4.8._
     */
    function verifyCallResultFromTarget(
        address target,
        bool success,
        bytes memory returndata,
        string memory errorMessage
    ) internal view returns (bytes memory) {
        if (success) {
            if (returndata.length == 0) {
                // only check isContract if the call was successful and the return data is empty
                // otherwise we already know that it was a contract
                require(isContract(target), "Address: call to non-contract");
            }
            return returndata;
        } else {
            _revert(returndata, errorMessage);
        }
    }

    /**
     * @dev Tool to verify that a low level call was successful, and revert if it wasn't, either by bubbling the
     * revert reason or 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 {
            _revert(returndata, errorMessage);
        }
    }

    function _revert(bytes memory returndata, string memory errorMessage) private pure {
        // 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
            /// @solidity memory-safe-assembly
            assembly {
                let returndata_size := mload(returndata)
                revert(add(32, returndata), returndata_size)
            }
        } else {
            revert(errorMessage);
        }
    }
}

// File: @openzeppelin/contracts/token/ERC20/utils/SafeERC20.sol

// OpenZeppelin Contracts (last updated v4.9.3) (token/ERC20/utils/SafeERC20.sol)




/**
 * @title SafeERC20
 * @dev Wrappers around ERC20 operations that throw on failure (when the token
 * contract returns false). Tokens that return no value (and instead revert or
 * throw on failure) are also supported, non-reverting calls are assumed to be
 * successful.
 * To use this library you can add a `using SafeERC20 for IERC20;` statement to your contract,
 * which allows you to call the safe operations as `token.safeTransfer(...)`, etc.
 */
library SafeERC20 {
    using Address for address;

    /**
     * @dev Transfer `value` amount of `token` from the calling contract to `to`. If `token` returns no value,
     * non-reverting calls are assumed to be successful.
     */
    function safeTransfer(IERC20 token, address to, uint256 value) internal {
        _callOptionalReturn(token, abi.encodeWithSelector(token.transfer.selector, to, value));
    }

    /**
     * @dev Transfer `value` amount of `token` from `from` to `to`, spending the approval given by `from` to the
     * calling contract. If `token` returns no value, non-reverting calls are assumed to be successful.
     */
    function safeTransferFrom(IERC20 token, address from, address to, uint256 value) internal {
        _callOptionalReturn(token, abi.encodeWithSelector(token.transferFrom.selector, from, to, value));
    }

    /**
     * @dev Deprecated. This function has issues similar to the ones found in
     * {IERC20-approve}, and its usage is discouraged.
     *
     * Whenever possible, use {safeIncreaseAllowance} and
     * {safeDecreaseAllowance} instead.
     */
    function safeApprove(IERC20 token, address spender, uint256 value) internal {
        // safeApprove should only be called when setting an initial allowance,
        // or when resetting it to zero. To increase and decrease it, use
        // 'safeIncreaseAllowance' and 'safeDecreaseAllowance'
        require(
            (value == 0) || (token.allowance(address(this), spender) == 0),
            "SafeERC20: approve from non-zero to non-zero allowance"
        );
        _callOptionalReturn(token, abi.encodeWithSelector(token.approve.selector, spender, value));
    }

    /**
     * @dev Increase the calling contract's allowance toward `spender` by `value`. If `token` returns no value,
     * non-reverting calls are assumed to be successful.
     */
    function safeIncreaseAllowance(IERC20 token, address spender, uint256 value) internal {
        uint256 oldAllowance = token.allowance(address(this), spender);
        _callOptionalReturn(token, abi.encodeWithSelector(token.approve.selector, spender, oldAllowance + value));
    }

    /**
     * @dev Decrease the calling contract's allowance toward `spender` by `value`. If `token` returns no value,
     * non-reverting calls are assumed to be successful.
     */
    function safeDecreaseAllowance(IERC20 token, address spender, uint256 value) internal {
        unchecked {
            uint256 oldAllowance = token.allowance(address(this), spender);
            require(oldAllowance >= value, "SafeERC20: decreased allowance below zero");
            _callOptionalReturn(token, abi.encodeWithSelector(token.approve.selector, spender, oldAllowance - value));
        }
    }

    /**
     * @dev Set the calling contract's allowance toward `spender` to `value`. If `token` returns no value,
     * non-reverting calls are assumed to be successful. Meant to be used with tokens that require the approval
     * to be set to zero before setting it to a non-zero value, such as USDT.
     */
    function forceApprove(IERC20 token, address spender, uint256 value) internal {
        bytes memory approvalCall = abi.encodeWithSelector(token.approve.selector, spender, value);

        if (!_callOptionalReturnBool(token, approvalCall)) {
            _callOptionalReturn(token, abi.encodeWithSelector(token.approve.selector, spender, 0));
            _callOptionalReturn(token, approvalCall);
        }
    }

    /**
     * @dev Use a ERC-2612 signature to set the `owner` approval toward `spender` on `token`.
     * Revert on invalid signature.
     */
    function safePermit(
        IERC20Permit token,
        address owner,
        address spender,
        uint256 value,
        uint256 deadline,
        uint8 v,
        bytes32 r,
        bytes32 s
    ) internal {
        uint256 nonceBefore = token.nonces(owner);
        token.permit(owner, spender, value, deadline, v, r, s);
        uint256 nonceAfter = token.nonces(owner);
        require(nonceAfter == nonceBefore + 1, "SafeERC20: permit did not succeed");
    }

    /**
     * @dev Imitates a Solidity high-level call (i.e. a regular function call to a contract), relaxing the requirement
     * on the return value: the return value is optional (but if data is returned, it must not be false).
     * @param token The token targeted by the call.
     * @param data The call data (encoded using abi.encode or one of its variants).
     */
    function _callOptionalReturn(IERC20 token, bytes memory data) private {
        // We need to perform a low level call here, to bypass Solidity's return data size checking mechanism, since
        // we're implementing it ourselves. We use {Address-functionCall} to perform this call, which verifies that
        // the target address contains contract code and also asserts for success in the low-level call.

        bytes memory returndata = address(token).functionCall(data, "SafeERC20: low-level call failed");
        require(returndata.length == 0 || abi.decode(returndata, (bool)), "SafeERC20: ERC20 operation did not succeed");
    }

    /**
     * @dev Imitates a Solidity high-level call (i.e. a regular function call to a contract), relaxing the requirement
     * on the return value: the return value is optional (but if data is returned, it must not be false).
     * @param token The token targeted by the call.
     * @param data The call data (encoded using abi.encode or one of its variants).
     *
     * This is a variant of {_callOptionalReturn} that silents catches all reverts and returns a bool instead.
     */
    function _callOptionalReturnBool(IERC20 token, bytes memory data) private returns (bool) {
        // We need to perform a low level call here, to bypass Solidity's return data size checking mechanism, since
        // we're implementing it ourselves. We cannot use {Address-functionCall} here since this should return false
        // and not revert is the subcall reverts.

        (bool success, bytes memory returndata) = address(token).call(data);
        return
            success && (returndata.length == 0 || abi.decode(returndata, (bool))) && Address.isContract(address(token));
    }
}

// File: @openzeppelin/contracts/security/ReentrancyGuard.sol

// OpenZeppelin Contracts (last updated v4.9.0) (security/ReentrancyGuard.sol)


/**
 * @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() {
        _nonReentrantBefore();
        _;
        _nonReentrantAfter();
    }

    function _nonReentrantBefore() private {
        // On the first call to nonReentrant, _status will be _NOT_ENTERED
        require(_status != _ENTERED, "ReentrancyGuard: reentrant call");

        // Any calls to nonReentrant after this point will fail
        _status = _ENTERED;
    }

    function _nonReentrantAfter() private {
        // By storing the original value once again, a refund is triggered (see
        // https://eips.ethereum.org/EIPS/eip-2200)
        _status = _NOT_ENTERED;
    }

    /**
     * @dev Returns true if the reentrancy guard is currently set to "entered", which indicates there is a
     * `nonReentrant` function in the call stack.
     */
    function _reentrancyGuardEntered() internal view returns (bool) {
        return _status == _ENTERED;
    }
}

// File: @openzeppelin/contracts/utils/Counters.sol

// OpenZeppelin Contracts v4.4.1 (utils/Counters.sol)

/**
 * @title Counters
 * @author Matt Condon (@shrugs)
 * @dev Provides counters that can only be incremented, decremented or reset. This can be used e.g. to track the number
 * of elements in a mapping, issuing ERC721 ids, or counting request ids.
 *
 * Include with `using Counters for Counters.Counter;`
 */
library Counters {
    struct Counter {
        // This variable should never be directly accessed by users of the library: interactions must be restricted to
        // the library's function. As of Solidity v0.5.2, this cannot be enforced, though there is a proposal to add
        // this feature: see https://github.com/ethereum/solidity/issues/4637
        uint256 _value; // default: 0
    }

    function current(Counter storage counter) internal view returns (uint256) {
        return counter._value;
    }

    function increment(Counter storage counter) internal {
        unchecked {
            counter._value += 1;
        }
    }

    function decrement(Counter storage counter) internal {
        uint256 value = counter._value;
        require(value > 0, "Counter: decrement overflow");
        unchecked {
            counter._value = value - 1;
        }
    }

    function reset(Counter storage counter) internal {
        counter._value = 0;
    }
}

// File: contracts/MerkleTreeWithHistory.sol

interface IHasher {
  function MiMCSponge(uint256 in_xL, uint256 in_xR) external pure returns (uint256 xL, uint256 xR);
}

contract MerkleTreeWithHistory {
  uint256 public constant FIELD_SIZE = 21888242871839275222246405745257275088548364400416034343698204186575808495617;
  uint256 public constant ZERO_VALUE = 21663839004416932945382355908790599225266501822907911457504978515578255421292; // = keccak256("tornado") % FIELD_SIZE
  IHasher public immutable hasher;

  uint32 public levels;

  // the following variables are made public for easier testing and debugging and
  // are not supposed to be accessed in regular code

  // filledSubtrees and roots could be bytes32[size], but using mappings makes it cheaper because
  // it removes index range check on every interaction
  mapping(uint256 => bytes32) public filledSubtrees;
  mapping(uint256 => bytes32) public roots;
  uint32 public constant ROOT_HISTORY_SIZE = 30;
  uint32 public currentRootIndex = 0;
  uint32 public nextIndex = 0;

  constructor(uint32 _levels, IHasher _hasher) {
    require(_levels > 0, "_levels should be greater than zero");
    require(_levels < 32, "_levels should be less than 32");
    levels = _levels;
    hasher = _hasher;

    for (uint32 i = 0; i < _levels; i++) {
      filledSubtrees[i] = zeros(i);
    }

    roots[0] = zeros(_levels - 1);
  }

  /**
    @dev Hash 2 tree leaves, returns MiMC(_left, _right)
  */
  function hashLeftRight(
    IHasher _hasher,
    bytes32 _left,
    bytes32 _right
  ) public pure returns (bytes32) {
    require(uint256(_left) < FIELD_SIZE, "_left should be inside the field");
    require(uint256(_right) < FIELD_SIZE, "_right should be inside the field");
    uint256 R = uint256(_left);
    uint256 C = 0;
    (R, C) = _hasher.MiMCSponge(R, C);
    R = addmod(R, uint256(_right), FIELD_SIZE);
    (R, C) = _hasher.MiMCSponge(R, C);
    return bytes32(R);
  }

  function _insert(bytes32 _leaf) internal returns (uint32 index) {
    uint32 _nextIndex = nextIndex;
    require(_nextIndex != uint32(2)**levels, "Merkle tree is full. No more leaves can be added");
    uint32 currentIndex = _nextIndex;
    bytes32 currentLevelHash = _leaf;
    bytes32 left;
    bytes32 right;

    for (uint32 i = 0; i < levels; i++) {
      if (currentIndex % 2 == 0) {
        left = currentLevelHash;
        right = zeros(i);
        filledSubtrees[i] = currentLevelHash;
      } else {
        left = filledSubtrees[i];
        right = currentLevelHash;
      }
      currentLevelHash = hashLeftRight(hasher, left, right);
      currentIndex /= 2;
    }

    uint32 newRootIndex = (currentRootIndex + 1) % ROOT_HISTORY_SIZE;
    currentRootIndex = newRootIndex;
    roots[newRootIndex] = currentLevelHash;
    nextIndex = _nextIndex + 1;
    return _nextIndex;
  }

  /**
    @dev Whether the root is present in the root history
  */
  function isKnownRoot(bytes32 _root) public view returns (bool) {
    if (_root == 0) {
      return false;
    }
    uint32 _currentRootIndex = currentRootIndex;
    uint32 i = _currentRootIndex;
    do {
      if (_root == roots[i]) {
        return true;
      }
      if (i == 0) {
        i = ROOT_HISTORY_SIZE;
      }
      i--;
    } while (i != _currentRootIndex);
    return false;
  }

  /**
    @dev Returns the last root
  */
  function getLastRoot() public view returns (bytes32) {
    return roots[currentRootIndex];
  }

  /// @dev provides Zero (Empty) elements for a MiMC MerkleTree. Up to 32 levels
  function zeros(uint256 i) public pure returns (bytes32) {
    if (i == 0) return bytes32(0x2fe54c60d3acabf3343a35b6eba15db4821b340f76e741e2249685ed4899af6c);
    else if (i == 1) return bytes32(0x256a6135777eee2fd26f54b8b7037a25439d5235caee224154186d2b8a52e31d);
    else if (i == 2) return bytes32(0x1151949895e82ab19924de92c40a3d6f7bcb60d92b00504b8199613683f0c200);
    else if (i == 3) return bytes32(0x20121ee811489ff8d61f09fb89e313f14959a0f28bb428a20dba6b0b068b3bdb);
    else if (i == 4) return bytes32(0x0a89ca6ffa14cc462cfedb842c30ed221a50a3d6bf022a6a57dc82ab24c157c9);
    else if (i == 5) return bytes32(0x24ca05c2b5cd42e890d6be94c68d0689f4f21c9cec9c0f13fe41d566dfb54959);
    else if (i == 6) return bytes32(0x1ccb97c932565a92c60156bdba2d08f3bf1377464e025cee765679e604a7315c);
    else if (i == 7) return bytes32(0x19156fbd7d1a8bf5cba8909367de1b624534ebab4f0f79e003bccdd1b182bdb4);
    else if (i == 8) return bytes32(0x261af8c1f0912e465744641409f622d466c3920ac6e5ff37e36604cb11dfff80);
    else if (i == 9) return bytes32(0x0058459724ff6ca5a1652fcbc3e82b93895cf08e975b19beab3f54c217d1c007);
    else if (i == 10) return bytes32(0x1f04ef20dee48d39984d8eabe768a70eafa6310ad20849d4573c3c40c2ad1e30);
    else if (i == 11) return bytes32(0x1bea3dec5dab51567ce7e200a30f7ba6d4276aeaa53e2686f962a46c66d511e5);
    else if (i == 12) return bytes32(0x0ee0f941e2da4b9e31c3ca97a40d8fa9ce68d97c084177071b3cb46cd3372f0f);
    else if (i == 13) return bytes32(0x1ca9503e8935884501bbaf20be14eb4c46b89772c97b96e3b2ebf3a36a948bbd);
    else if (i == 14) return bytes32(0x133a80e30697cd55d8f7d4b0965b7be24057ba5dc3da898ee2187232446cb108);
    else if (i == 15) return bytes32(0x13e6d8fc88839ed76e182c2a779af5b2c0da9dd18c90427a644f7e148a6253b6);
    else if (i == 16) return bytes32(0x1eb16b057a477f4bc8f572ea6bee39561098f78f15bfb3699dcbb7bd8db61854);
    else if (i == 17) return bytes32(0x0da2cb16a1ceaabf1c16b838f7a9e3f2a3a3088d9e0a6debaa748114620696ea);
    else if (i == 18) return bytes32(0x24a3b3d822420b14b5d8cb6c28a574f01e98ea9e940551d2ebd75cee12649f9d);
    else if (i == 19) return bytes32(0x198622acbd783d1b0d9064105b1fc8e4d8889de95c4c519b3f635809fe6afc05);
    else if (i == 20) return bytes32(0x29d7ed391256ccc3ea596c86e933b89ff339d25ea8ddced975ae2fe30b5296d4);
    else if (i == 21) return bytes32(0x19be59f2f0413ce78c0c3703a3a5451b1d7f39629fa33abd11548a76065b2967);
    else if (i == 22) return bytes32(0x1ff3f61797e538b70e619310d33f2a063e7eb59104e112e95738da1254dc3453);
    else if (i == 23) return bytes32(0x10c16ae9959cf8358980d9dd9616e48228737310a10e2b6b731c1a548f036c48);
    else if (i == 24) return bytes32(0x0ba433a63174a90ac20992e75e3095496812b652685b5e1a2eae0b1bf4e8fcd1);
    else if (i == 25) return bytes32(0x019ddb9df2bc98d987d0dfeca9d2b643deafab8f7036562e627c3667266a044c);
    else if (i == 26) return bytes32(0x2d3c88b23175c5a5565db928414c66d1912b11acf974b2e644caaac04739ce99);
    else if (i == 27) return bytes32(0x2eab55f6ae4e66e32c5189eed5c470840863445760f5ed7e7b69b2a62600f354);
    else if (i == 28) return bytes32(0x002df37a2642621802383cf952bf4dd1f32e05433beeb1fd41031fb7eace979d);
    else if (i == 29) return bytes32(0x104aeb41435db66c3e62feccc1d6f5d98d0a0ed75d1374db457cf462e3a1f427);
    else if (i == 30) return bytes32(0x1f3c6fd858e9a7d4b0d1f38e256a09d81d5a5e3c963987e2d4b814cfab7c6ebb);
    else if (i == 31) return bytes32(0x2c7a07d20dff79d01fecedc1134284a8d08436606c93693b67e333f671bf69cc);
    else revert("Index out of bounds");
  }
}

interface IVerifier {
  function verifyProof(bytes memory _proof, uint256[6] memory _input) external view returns (bool);
}

interface IReward {
  function stake(bytes32 _nullifierHash) external;
  function withdraw(bytes32 _nullifierHash, address payable _recipient) external;
}

abstract contract Tornado is MerkleTreeWithHistory, ReentrancyGuard {
    using Counters for Counters.Counter;
    Counters.Counter private _stakedCounter;

    uint256 public denomination;
    mapping(bytes32 => Status) public nullifierHashes;
    // we store all commitments just to prevent accidental deposits with the same commitment
    mapping(bytes32 => bool) public commitments;
    IVerifier public verifier;
    IReward public rewarder;

    // reserve pool address
    address public reserve;

    // operator can update snark verification key
    // after the final trusted setup ceremony operator rights are supposed to be transferred to zero address
    address public operator;
    modifier onlyOperator {
        require(msg.sender == operator, "Only operator can call this function.");
        _;
    }

    address public governance;
    modifier onlyGovernance {
        require(msg.sender == governance, "Only governance can call this function.");
        _;
    }

    enum Status {
        Deposited,
        Staked,
        Withdrawed
    }

    uint public reserveFeeRelayerPercent = 0;
    uint public reserveFeeRelayerMaxPercent = 100;

    event Deposit(bytes32 indexed commitments, uint32 leafIndex, uint256 timestamp);
    event Withdrawal(address to, bytes32 nullifierHashes, address indexed relayer, uint256 fee);
    event StakedNote(bytes32 nullifierHash, uint256 timestamp);
    event UnstakedWithdrawal(address indexed recipient, bytes32 nullifierHash);

    constructor(
        IVerifier _verifier,
        uint256 _denomination,
        uint32 _merkleTreeHieght,
        IHasher _hasher,
        address _operator,
        address _governance,
        address _reserve
    ) MerkleTreeWithHistory(_merkleTreeHieght, _hasher) {
        require(_denomination > 0, "denomination should be greater than zero");
        verifier = _verifier;
        denomination = _denomination;
        operator = _operator;
        governance = _governance;
        reserve = _reserve;
    }

    function deposit(bytes32 _commitment) public payable nonReentrant {
        require(!commitments[_commitment], "The commitment has been submitted");

        uint32 insertedIndex = _insert(_commitment);
        commitments[_commitment] = true;
        _processDeposit();

        emit Deposit(_commitment, insertedIndex, block.timestamp);
    }

    function _processDeposit() internal virtual;

    function withdraw(
        bytes calldata _proof,
        bytes32 _root,
        bytes32 _nullifierHash,
        address payable _recipient,
        address payable _relayer,
        uint256 _fee,
        uint256 _refund
    ) external payable nonReentrant {
        require(_fee <= denomination, "Fee exceeds transfer value");
        require(nullifierHashes[_nullifierHash] == Status.Deposited, "The note has been already spent");
        require(isKnownRoot(_root), "Cannot find your merkle root");
        require(verifier.verifyProof(_proof, [uint256(_root), uint256(_nullifierHash), uint256(uint160(address(_recipient))), 
            uint256(uint160(address(_relayer))), _fee, _refund]), "Invalid withdraw proof");

        nullifierHashes[_nullifierHash] = Status.Withdrawed;
        _processWithdraw(_recipient, _relayer, _fee, _refund);

        emit Withdrawal(_recipient, _nullifierHash, _relayer, _fee);
    }

    function stakeNote(        
        bytes calldata _proof,
        bytes32 _root,
        bytes32 _nullifierHash,
        address payable _recipient,
        address payable _relayer,
        uint256 _fee,
        uint256 _refund
    ) external payable nonReentrant {
        require(nullifierHashes[_nullifierHash] == Status.Deposited, "The note has been already spent");
        require(isKnownRoot(_root), "Cannot find your merkle root"); // Make sure to use a recent one
        require(verifier.verifyProof(_proof, [uint256(_root), uint256(_nullifierHash), uint256(uint160(address(_recipient))), 
            uint256(uint160(address(_relayer))), _fee, _refund]), "Invalid withdraw proof");

        nullifierHashes[_nullifierHash] = Status.Staked;
        rewarder.stake(_nullifierHash);
        _stakedCounter.increment();
        emit StakedNote(_nullifierHash, block.timestamp);
    }

    function unstakeAndWithdraw(
        bytes calldata _proof,
        bytes32 _root,
        bytes32 _nullifierHash,        
        address payable _recipient,
        address payable _relayer,
        uint256 _fee,
        uint256 _refund
    ) external payable nonReentrant {
        require(_fee <= denomination, "Fee exceeds transfer value");
        require(nullifierHashes[_nullifierHash] == Status.Staked, "unstaked");
        require(isKnownRoot(_root), "Cannot find your merkle root");
        require(verifier.verifyProof(_proof, [uint256(_root), uint256(_nullifierHash), uint256(uint160(address(_recipient))), 
            uint256(uint160(address(_relayer))), _fee, _refund]), "Invalid withdraw proof");

        nullifierHashes[_nullifierHash] = Status.Withdrawed;
        _processWithdraw(_recipient, _relayer, _fee, _refund);
        emit Withdrawal(_recipient, _nullifierHash, _relayer, _fee);
        rewarder.withdraw(_nullifierHash, _recipient);
        _stakedCounter.decrement();
        emit UnstakedWithdrawal(_recipient, _nullifierHash);
    }

    function _processWithdraw(
        address payable _recipient,
        address payable _relayer,
        uint256 _fee,
        uint256 _refund
    ) internal virtual;

    function isSpent(bytes32 _nullifierHash) public view returns (bool) {
        return nullifierHashes[_nullifierHash] >= Status.Withdrawed;
    }

    /** @dev whether an array of notes is already spent */
    function isSpentArray(bytes32[] calldata _nullifierHashes) external view returns(bool[] memory spent) {
        spent = new bool[](_nullifierHashes.length);
        for(uint i = 0; i < _nullifierHashes.length; i++) {
            if (isSpent(_nullifierHashes[i])) {
                spent[i] = true;
            }
        }
    }

    function updateRewarder(address _newRewarder) external onlyOperator {
        rewarder = IReward(_newRewarder);
    }

    /** @dev operator can change his address */
    function changeOperator(address _newOperator) external onlyOperator {
        operator = _newOperator;
    }

    /** @dev get current staked count */
    function getStakedCount() public view returns (uint256) {
        return _stakedCounter.current();
    }

    /** @dev set governance address */
    function setGovernance(address _governance) external onlyGovernance {
        governance = _governance;
    }

    /** @dev set reserve address */
    function setReserveAddress(address _newReserve) external onlyGovernance {
        reserve = _newReserve;
    }

    /** @dev set reserve fee */
    function setReserveFeeRelayerPercent(uint _reserveFeeRelayerPercent) external onlyGovernance {
        require(_reserveFeeRelayerPercent < reserveFeeRelayerMaxPercent,"invalid reserve fee percent.");
        reserveFeeRelayerPercent = _reserveFeeRelayerPercent;
    }
}


contract ETHTornado is Tornado {
    using SafeERC20 for IERC20;

    constructor(
        IVerifier _verifier,
        uint256 _denomination,
        uint32 _merkleTreeHeight,
        IHasher _hasher,
        address _operator,
        address _governance,
        address _reserve
    ) Tornado(_verifier, _denomination, _merkleTreeHeight, _hasher, _operator, _governance, _reserve) {}

    function _processDeposit() internal override {
        require(msg.value == denomination, "Please send `mixDenomination` ETH along with transaction");
    }

    function _processWithdraw(
        address payable _recipient,
        address payable _relayer,
        uint256 _fee,
        uint256 _refund
    ) internal override {
        require(msg.value == 0, "msg.value is supposed to be zero for ETH instance");
        require(_refund == 0, "refund value is supposed to be zero for ETH instance"); // refund is used by ERC20Tornado

        uint256 _reserveFee = 0;
        uint256 _relayFee = _fee;
        if (_fee > 0) {
            _reserveFee = _fee * reserveFeeRelayerPercent / reserveFeeRelayerMaxPercent;
            _relayFee = _fee - _reserveFee;
            (bool success_relayer, ) = _relayer.call{value: _relayFee}("");
            require(success_relayer, "payment to _relayer did not go thru");
        }

        if (_reserveFee > 0) {
            (bool success_fee, ) = reserve.call{value:_reserveFee}("");
            require(success_fee, "payment to reserve did not go thru");
        }

        (bool success, ) = _recipient.call{value:denomination - _reserveFee - _relayFee}("");
        require(success, "payment to _recipient did not go thru");
    }

      /** @dev seize accidental sent erc20 token */
    function seize(IERC20 _token, uint amount) external onlyGovernance {
        _token.transfer(governance, amount);
    }
}

contract ERC20Tornado is Tornado {
  using SafeERC20 for IERC20;
  IERC20 public token;

  constructor(
    IVerifier _verifier,
    uint256 _denomination,
    uint32 _merkleTreeHeight,
    IHasher _hasher,
    address _operator,
    address _governance,
    address _reserve,
    IERC20 _token
  ) Tornado(_verifier, _denomination, _merkleTreeHeight, _hasher,_operator, _governance, _reserve) {
    token = _token;
  }

  function _processDeposit() internal override {
    require(msg.value == 0, "ETH value is supposed to be 0 for ERC20 instance");
    token.safeTransferFrom(msg.sender, address(this), denomination);
  }

  function _processWithdraw(
    address payable _recipient,
    address payable _relayer,
    uint256 _fee,
    uint256 _refund
  ) internal override {
    require(msg.value == _refund, "Incorrect refund amount received by the contract");

    uint256 _reserveFee = 0;
    uint256 _relayFee = _fee;
    if (_fee > 0) {
      _reserveFee = _fee * reserveFeeRelayerPercent / reserveFeeRelayerMaxPercent;
      _relayFee = _fee - _reserveFee;
      token.safeTransfer(_relayer, _relayFee);
    }

    if (_reserveFee>0){
      token.safeTransfer(reserve, _reserveFee);
    }
    
    token.safeTransfer(_recipient, denomination- _reserveFee - _relayFee);
    

    if (_refund > 0) {
      (bool success, ) = _recipient.call{ value: _refund }("");
      if (!success) {
        // let's return _refund back to the relayer
        _relayer.transfer(_refund);
      }
    }
  }

    /** @dev seize accidental sent token */
  function seize(IERC20 _token, uint amount) external onlyGovernance {
    require(address(_token) != address(token), "cannot be token");
    _token.transfer(governance, amount);
  }
}

//////////////////////miner

library Math {
    enum Rounding {
        Down, // Toward negative infinity
        Up, // Toward infinity
        Zero // Toward zero
    }

    /**
     * @dev Returns the largest of two numbers.
     */
    function max(uint256 a, uint256 b) internal pure returns (uint256) {
        return a > b ? a : b;
    }

    /**
     * @dev Returns the smallest of two numbers.
     */
    function min(uint256 a, uint256 b) internal pure returns (uint256) {
        return a < b ? a : b;
    }

    /**
     * @dev Returns the average of two numbers. The result is rounded towards
     * zero.
     */
    function average(uint256 a, uint256 b) internal pure returns (uint256) {
        // (a + b) / 2 can overflow.
        return (a & b) + (a ^ b) / 2;
    }

    /**
     * @dev Returns the ceiling of the division of two numbers.
     *
     * This differs from standard division with `/` in that it rounds up instead
     * of rounding down.
     */
    function ceilDiv(uint256 a, uint256 b) internal pure returns (uint256) {
        // (a + b - 1) / b can overflow on addition, so we distribute.
        return a == 0 ? 0 : (a - 1) / b + 1;
    }

    /**
     * @notice Calculates floor(x * y / denominator) with full precision. Throws if result overflows a uint256 or denominator == 0
     * @dev Original credit to Remco Bloemen under MIT license (https://xn--2-umb.com/21/muldiv)
     * with further edits by Uniswap Labs also under MIT license.
     */
    function mulDiv(uint256 x, uint256 y, uint256 denominator) internal pure returns (uint256 result) {
        unchecked {
            // 512-bit multiply [prod1 prod0] = x * y. Compute the product mod 2^256 and mod 2^256 - 1, then use
            // use the Chinese Remainder Theorem to reconstruct the 512 bit result. The result is stored in two 256
            // variables such that product = prod1 * 2^256 + prod0.
            uint256 prod0; // Least significant 256 bits of the product
            uint256 prod1; // Most significant 256 bits of the product
            assembly {
                let mm := mulmod(x, y, not(0))
                prod0 := mul(x, y)
                prod1 := sub(sub(mm, prod0), lt(mm, prod0))
            }

            // Handle non-overflow cases, 256 by 256 division.
            if (prod1 == 0) {
                // Solidity will revert if denominator == 0, unlike the div opcode on its own.
                // The surrounding unchecked block does not change this fact.
                // See https://docs.soliditylang.org/en/latest/control-structures.html#checked-or-unchecked-arithmetic.
                return prod0 / denominator;
            }

            // Make sure the result is less than 2^256. Also prevents denominator == 0.
            require(denominator > prod1, "Math: mulDiv overflow");

            ///////////////////////////////////////////////
            // 512 by 256 division.
            ///////////////////////////////////////////////

            // Make division exact by subtracting the remainder from [prod1 prod0].
            uint256 remainder;
            assembly {
                // Compute remainder using mulmod.
                remainder := mulmod(x, y, denominator)

                // Subtract 256 bit number from 512 bit number.
                prod1 := sub(prod1, gt(remainder, prod0))
                prod0 := sub(prod0, remainder)
            }

            // Factor powers of two out of denominator and compute largest power of two divisor of denominator. Always >= 1.
            // See https://cs.stackexchange.com/q/138556/92363.

            // Does not overflow because the denominator cannot be zero at this stage in the function.
            uint256 twos = denominator & (~denominator + 1);
            assembly {
                // Divide denominator by twos.
                denominator := div(denominator, twos)

                // Divide [prod1 prod0] by twos.
                prod0 := div(prod0, twos)

                // Flip twos such that it is 2^256 / twos. If twos is zero, then it becomes one.
                twos := add(div(sub(0, twos), twos), 1)
            }

            // Shift in bits from prod1 into prod0.
            prod0 |= prod1 * twos;

            // Invert denominator mod 2^256. Now that denominator is an odd number, it has an inverse modulo 2^256 such
            // that denominator * inv = 1 mod 2^256. Compute the inverse by starting with a seed that is correct for
            // four bits. That is, denominator * inv = 1 mod 2^4.
            uint256 inverse = (3 * denominator) ^ 2;

            // Use the Newton-Raphson iteration to improve the precision. Thanks to Hensel's lifting lemma, this also works
            // in modular arithmetic, doubling the correct bits in each step.
            inverse *= 2 - denominator * inverse; // inverse mod 2^8
            inverse *= 2 - denominator * inverse; // inverse mod 2^16
            inverse *= 2 - denominator * inverse; // inverse mod 2^32
            inverse *= 2 - denominator * inverse; // inverse mod 2^64
            inverse *= 2 - denominator * inverse; // inverse mod 2^128
            inverse *= 2 - denominator * inverse; // inverse mod 2^256

            // Because the division is now exact we can divide by multiplying with the modular inverse of denominator.
            // This will give us the correct result modulo 2^256. Since the preconditions guarantee that the outcome is
            // less than 2^256, this is the final result. We don't need to compute the high bits of the result and prod1
            // is no longer required.
            result = prod0 * inverse;
            return result;
        }
    }

    /**
     * @notice Calculates x * y / denominator with full precision, following the selected rounding direction.
     */
    function mulDiv(uint256 x, uint256 y, uint256 denominator, Rounding rounding) internal pure returns (uint256) {
        uint256 result = mulDiv(x, y, denominator);
        if (rounding == Rounding.Up && mulmod(x, y, denominator) > 0) {
            result += 1;
        }
        return result;
    }

    /**
     * @dev Returns the square root of a number. If the number is not a perfect square, the value is rounded down.
     *
     * Inspired by Henry S. Warren, Jr.'s "Hacker's Delight" (Chapter 11).
     */
    function sqrt(uint256 a) internal pure returns (uint256) {
        if (a == 0) {
            return 0;
        }

        // For our first guess, we get the biggest power of 2 which is smaller than the square root of the target.
        //
        // We know that the "msb" (most significant bit) of our target number `a` is a power of 2 such that we have
        // `msb(a) <= a < 2*msb(a)`. This value can be written `msb(a)=2**k` with `k=log2(a)`.
        //
        // This can be rewritten `2**log2(a) <= a < 2**(log2(a) + 1)`
        // → `sqrt(2**k) <= sqrt(a) < sqrt(2**(k+1))`
        // → `2**(k/2) <= sqrt(a) < 2**((k+1)/2) <= 2**(k/2 + 1)`
        //
        // Consequently, `2**(log2(a) / 2)` is a good first approximation of `sqrt(a)` with at least 1 correct bit.
        uint256 result = 1 << (log2(a) >> 1);

        // At this point `result` is an estimation with one bit of precision. We know the true value is a uint128,
        // since it is the square root of a uint256. Newton's method converges quadratically (precision doubles at
        // every iteration). We thus need at most 7 iteration to turn our partial result with one bit of precision
        // into the expected uint128 result.
        unchecked {
            result = (result + a / result) >> 1;
            result = (result + a / result) >> 1;
            result = (result + a / result) >> 1;
            result = (result + a / result) >> 1;
            result = (result + a / result) >> 1;
            result = (result + a / result) >> 1;
            result = (result + a / result) >> 1;
            return min(result, a / result);
        }
    }

    /**
     * @notice Calculates sqrt(a), following the selected rounding direction.
     */
    function sqrt(uint256 a, Rounding rounding) internal pure returns (uint256) {
        unchecked {
            uint256 result = sqrt(a);
            return result + (rounding == Rounding.Up && result * result < a ? 1 : 0);
        }
    }

    /**
     * @dev Return the log in base 2, rounded down, of a positive value.
     * Returns 0 if given 0.
     */
    function log2(uint256 value) internal pure returns (uint256) {
        uint256 result = 0;
        unchecked {
            if (value >> 128 > 0) {
                value >>= 128;
                result += 128;
            }
            if (value >> 64 > 0) {
                value >>= 64;
                result += 64;
            }
            if (value >> 32 > 0) {
                value >>= 32;
                result += 32;
            }
            if (value >> 16 > 0) {
                value >>= 16;
                result += 16;
            }
            if (value >> 8 > 0) {
                value >>= 8;
                result += 8;
            }
            if (value >> 4 > 0) {
                value >>= 4;
                result += 4;
            }
            if (value >> 2 > 0) {
                value >>= 2;
                result += 2;
            }
            if (value >> 1 > 0) {
                result += 1;
            }
        }
        return result;
    }

    /**
     * @dev Return the log in base 2, following the selected rounding direction, of a positive value.
     * Returns 0 if given 0.
     */
    function log2(uint256 value, Rounding rounding) internal pure returns (uint256) {
        unchecked {
            uint256 result = log2(value);
            return result + (rounding == Rounding.Up && 1 << result < value ? 1 : 0);
        }
    }

    /**
     * @dev Return the log in base 10, rounded down, of a positive value.
     * Returns 0 if given 0.
     */
    function log10(uint256 value) internal pure returns (uint256) {
        uint256 result = 0;
        unchecked {
            if (value >= 10 ** 64) {
                value /= 10 ** 64;
                result += 64;
            }
            if (value >= 10 ** 32) {
                value /= 10 ** 32;
                result += 32;
            }
            if (value >= 10 ** 16) {
                value /= 10 ** 16;
                result += 16;
            }
            if (value >= 10 ** 8) {
                value /= 10 ** 8;
                result += 8;
            }
            if (value >= 10 ** 4) {
                value /= 10 ** 4;
                result += 4;
            }
            if (value >= 10 ** 2) {
                value /= 10 ** 2;
                result += 2;
            }
            if (value >= 10 ** 1) {
                result += 1;
            }
        }
        return result;
    }

    /**
     * @dev Return the log in base 10, following the selected rounding direction, of a positive value.
     * Returns 0 if given 0.
     */
    function log10(uint256 value, Rounding rounding) internal pure returns (uint256) {
        unchecked {
            uint256 result = log10(value);
            return result + (rounding == Rounding.Up && 10 ** result < value ? 1 : 0);
        }
    }

    /**
     * @dev Return the log in base 256, rounded down, of a positive value.
     * Returns 0 if given 0.
     *
     * Adding one to the result gives the number of pairs of hex symbols needed to represent `value` as a hex string.
     */
    function log256(uint256 value) internal pure returns (uint256) {
        uint256 result = 0;
        unchecked {
            if (value >> 128 > 0) {
                value >>= 128;
                result += 16;
            }
            if (value >> 64 > 0) {
                value >>= 64;
                result += 8;
            }
            if (value >> 32 > 0) {
                value >>= 32;
                result += 4;
            }
            if (value >> 16 > 0) {
                value >>= 16;
                result += 2;
            }
            if (value >> 8 > 0) {
                result += 1;
            }
        }
        return result;
    }

    /**
     * @dev Return the log in base 256, following the selected rounding direction, of a positive value.
     * Returns 0 if given 0.
     */
    function log256(uint256 value, Rounding rounding) internal pure returns (uint256) {
        unchecked {
            uint256 result = log256(value);
            return result + (rounding == Rounding.Up && 1 << (result << 3) < value ? 1 : 0);
        }
    }
}

abstract contract Context {
    function _msgSender() internal view virtual returns (address) {
        return msg.sender;
    }

    function _msgData() internal view virtual returns (bytes calldata) {
        return msg.data;
    }
}

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 Throws if called by any account other than the owner.
     */
    modifier onlyOwner() {
        _checkOwner();
        _;
    }

    /**
     * @dev Returns the address of the current owner.
     */
    function owner() public view virtual returns (address) {
        return _owner;
    }

    /**
     * @dev Throws if the sender is not the owner.
     */
    function _checkOwner() internal view virtual {
        require(owner() == _msgSender(), "Ownable: caller is not the owner");
    }

    /**
     * @dev Leaves the contract without owner. It will not be possible to call
     * `onlyOwner` functions. Can only be called by the current owner.
     *
     * NOTE: Renouncing ownership will leave the contract without an owner,
     * thereby disabling 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);
    }
}