// File: openzeppelin-solidity\contracts\math\SafeMath.sol

pragma solidity ^0.5.2;

/**
 * @title SafeMath
 * @dev Unsigned math operations with safety checks that revert on error
 */
library SafeMath {
    /**
     * @dev Multiplies two unsigned integers, reverts on overflow.
     */
    function mul(uint256 a, uint256 b) internal pure returns (uint256) {
        // Gas optimization: this is cheaper than requiring 'a' not being zero, but the
        // benefit is lost if 'b' is also tested.
        // See: https://github.com/OpenZeppelin/openzeppelin-solidity/pull/522
        if (a == 0) {
            return 0;
        }

        uint256 c = a * b;
        require(c / a == b);

        return c;
    }

    /**
     * @dev Integer division of two unsigned integers truncating the quotient, reverts on division by zero.
     */
    function div(uint256 a, uint256 b) internal pure returns (uint256) {
        // Solidity only automatically asserts when dividing by 0
        require(b > 0);
        uint256 c = a / b;
        // assert(a == b * c + a % b); // There is no case in which this doesn't hold

        return c;
    }

    /**
     * @dev Subtracts two unsigned integers, reverts on overflow (i.e. if subtrahend is greater than minuend).
     */
    function sub(uint256 a, uint256 b) internal pure returns (uint256) {
        require(b <= a);
        uint256 c = a - b;

        return c;
    }

    /**
     * @dev Adds two unsigned integers, reverts on overflow.
     */
    function add(uint256 a, uint256 b) internal pure returns (uint256) {
        uint256 c = a + b;
        require(c >= a);

        return c;
    }

    /**
     * @dev Divides two unsigned integers and returns the remainder (unsigned integer modulo),
     * reverts when dividing by zero.
     */
    function mod(uint256 a, uint256 b) internal pure returns (uint256) {
        require(b != 0);
        return a % b;
    }
}

// File: openzeppelin-solidity\contracts\ownership\Ownable.sol

pragma solidity ^0.5.2;

/**
 * @title Ownable
 * @dev The Ownable contract has an owner address, and provides basic authorization control
 * functions, this simplifies the implementation of "user permissions".
 */
contract Ownable {
    address private _owner;

    event OwnershipTransferred(address indexed previousOwner, address indexed newOwner);

    /**
     * @dev The Ownable constructor sets the original `owner` of the contract to the sender
     * account.
     */
    constructor () internal {
        _owner = msg.sender;
        emit OwnershipTransferred(address(0), _owner);
    }

    /**
     * @return the address of the owner.
     */
    function owner() public view returns (address) {
        return _owner;
    }

    /**
     * @dev Throws if called by any account other than the owner.
     */
    modifier onlyOwner() {
        require(isOwner());
        _;
    }

    /**
     * @return true if `msg.sender` is the owner of the contract.
     */
    function isOwner() public view returns (bool) {
        return msg.sender == _owner;
    }

    /**
     * @dev Allows the current owner to relinquish control of the contract.
     * It will not be possible to call the functions with the `onlyOwner`
     * modifier anymore.
     * @notice Renouncing ownership will leave the contract without an owner,
     * thereby removing any functionality that is only available to the owner.
     */
    function renounceOwnership() public onlyOwner {
        emit OwnershipTransferred(_owner, address(0));
        _owner = address(0);
    }

    /**
     * @dev Allows the current owner to transfer control of the contract to a newOwner.
     * @param newOwner The address to transfer ownership to.
     */
    function transferOwnership(address newOwner) public onlyOwner {
        _transferOwnership(newOwner);
    }

    /**
     * @dev Transfers control of the contract to a newOwner.
     * @param newOwner The address to transfer ownership to.
     */
    function _transferOwnership(address newOwner) internal {
        require(newOwner != address(0));
        emit OwnershipTransferred(_owner, newOwner);
        _owner = newOwner;
    }
}

// File: node_modules\openzeppelin-solidity\contracts\token\ERC20\IERC20.sol

pragma solidity ^0.5.2;

/**
 * @title ERC20 interface
 * @dev see https://eips.ethereum.org/EIPS/eip-20
 */
interface IERC20 {
    function transfer(address to, uint256 value) external returns (bool);

    function approve(address spender, uint256 value) external returns (bool);

    function transferFrom(address from, address to, uint256 value) external returns (bool);

    function totalSupply() external view returns (uint256);

    function balanceOf(address who) external view returns (uint256);

    function allowance(address owner, address spender) external view returns (uint256);

    event Transfer(address indexed from, address indexed to, uint256 value);

    event Approval(address indexed owner, address indexed spender, uint256 value);
}

// File: openzeppelin-solidity\contracts\token\ERC20\ERC20.sol

pragma solidity ^0.5.2;



/**
 * @title Standard ERC20 token
 *
 * @dev Implementation of the basic standard token.
 * https://eips.ethereum.org/EIPS/eip-20
 * Originally based on code by FirstBlood:
 * https://github.com/Firstbloodio/token/blob/master/smart_contract/FirstBloodToken.sol
 *
 * This implementation emits additional Approval events, allowing applications to reconstruct the allowance status for
 * all accounts just by listening to said events. Note that this isn't required by the specification, and other
 * compliant implementations may not do it.
 */
contract ERC20 is IERC20 {
    using SafeMath for uint256;

    mapping (address => uint256) private _balances;

    mapping (address => mapping (address => uint256)) private _allowed;

    uint256 private _totalSupply;

    /**
     * @dev Total number of tokens in existence
     */
    function totalSupply() public view returns (uint256) {
        return _totalSupply;
    }

    /**
     * @dev Gets the balance of the specified address.
     * @param owner The address to query the balance of.
     * @return A uint256 representing the amount owned by the passed address.
     */
    function balanceOf(address owner) public view returns (uint256) {
        return _balances[owner];
    }

    /**
     * @dev Function to check the amount of tokens that an owner allowed to a spender.
     * @param owner address The address which owns the funds.
     * @param spender address The address which will spend the funds.
     * @return A uint256 specifying the amount of tokens still available for the spender.
     */
    function allowance(address owner, address spender) public view returns (uint256) {
        return _allowed[owner][spender];
    }

    /**
     * @dev Transfer token to a specified address
     * @param to The address to transfer to.
     * @param value The amount to be transferred.
     */
    function transfer(address to, uint256 value) public returns (bool) {
        _transfer(msg.sender, to, value);
        return true;
    }

    /**
     * @dev Approve the passed address to spend the specified amount of tokens on behalf of msg.sender.
     * 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
     * @param spender The address which will spend the funds.
     * @param value The amount of tokens to be spent.
     */
    function approve(address spender, uint256 value) public returns (bool) {
        _approve(msg.sender, spender, value);
        return true;
    }

    /**
     * @dev Transfer tokens from one address to another.
     * Note that while this function emits an Approval event, this is not required as per the specification,
     * and other compliant implementations may not emit the event.
     * @param from address The address which you want to send tokens from
     * @param to address The address which you want to transfer to
     * @param value uint256 the amount of tokens to be transferred
     */
    function transferFrom(address from, address to, uint256 value) public returns (bool) {
        _transfer(from, to, value);
        _approve(from, msg.sender, _allowed[from][msg.sender].sub(value));
        return true;
    }

    /**
     * @dev Increase the amount of tokens that an owner allowed to a spender.
     * approve should be called when _allowed[msg.sender][spender] == 0. To increment
     * allowed value is better to use this function to avoid 2 calls (and wait until
     * the first transaction is mined)
     * From MonolithDAO Token.sol
     * Emits an Approval event.
     * @param spender The address which will spend the funds.
     * @param addedValue The amount of tokens to increase the allowance by.
     */
    function increaseAllowance(address spender, uint256 addedValue) public returns (bool) {
        _approve(msg.sender, spender, _allowed[msg.sender][spender].add(addedValue));
        return true;
    }

    /**
     * @dev Decrease the amount of tokens that an owner allowed to a spender.
     * approve should be called when _allowed[msg.sender][spender] == 0. To decrement
     * allowed value is better to use this function to avoid 2 calls (and wait until
     * the first transaction is mined)
     * From MonolithDAO Token.sol
     * Emits an Approval event.
     * @param spender The address which will spend the funds.
     * @param subtractedValue The amount of tokens to decrease the allowance by.
     */
    function decreaseAllowance(address spender, uint256 subtractedValue) public returns (bool) {
        _approve(msg.sender, spender, _allowed[msg.sender][spender].sub(subtractedValue));
        return true;
    }

    /**
     * @dev Transfer token for a specified addresses
     * @param from The address to transfer from.
     * @param to The address to transfer to.
     * @param value The amount to be transferred.
     */
    function _transfer(address from, address to, uint256 value) internal {
        require(to != address(0));

        _balances[from] = _balances[from].sub(value);
        _balances[to] = _balances[to].add(value);
        emit Transfer(from, to, value);
    }

    /**
     * @dev Internal function that mints an amount of the token and assigns it to
     * an account. This encapsulates the modification of balances such that the
     * proper events are emitted.
     * @param account The account that will receive the created tokens.
     * @param value The amount that will be created.
     */
    function _mint(address account, uint256 value) internal {
        require(account != address(0));

        _totalSupply = _totalSupply.add(value);
        _balances[account] = _balances[account].add(value);
        emit Transfer(address(0), account, value);
    }

    /**
     * @dev Internal function that burns an amount of the token of a given
     * account.
     * @param account The account whose tokens will be burnt.
     * @param value The amount that will be burnt.
     */
    function _burn(address account, uint256 value) internal {
        require(account != address(0));

        _totalSupply = _totalSupply.sub(value);
        _balances[account] = _balances[account].sub(value);
        emit Transfer(account, address(0), value);
    }

    /**
     * @dev Approve an address to spend another addresses' tokens.
     * @param owner The address that owns the tokens.
     * @param spender The address that will spend the tokens.
     * @param value The number of tokens that can be spent.
     */
    function _approve(address owner, address spender, uint256 value) internal {
        require(spender != address(0));
        require(owner != address(0));

        _allowed[owner][spender] = value;
        emit Approval(owner, spender, value);
    }

    /**
     * @dev Internal function that burns an amount of the token of a given
     * account, deducting from the sender's allowance for said account. Uses the
     * internal burn function.
     * Emits an Approval event (reflecting the reduced allowance).
     * @param account The account whose tokens will be burnt.
     * @param value The amount that will be burnt.
     */
    function _burnFrom(address account, uint256 value) internal {
        _burn(account, value);
        _approve(account, msg.sender, _allowed[account][msg.sender].sub(value));
    }
}

// File: contracts\Power.sol

pragma solidity ^0.5.2;


 /**
 * @title Power function by Bancor
 * @dev https://github.com/bancorprotocol/contracts
 *
 * Modified from the original by Slava Balasanov & Tarrence van As
 *
 * Split Power.sol out from BancorFormula.sol
 * https://github.com/bancorprotocol/contracts/blob/c9adc95e82fdfb3a0ada102514beb8ae00147f5d/solidity/contracts/converter/BancorFormula.sol
 *
 * Licensed to the Apache Software Foundation (ASF) under one or more contributor license agreements;
 * and to You under the Apache License, Version 2.0. "
 */
contract Power {
  string public version = "0.3";

  uint256 private constant ONE = 1;
  uint32 private constant MAX_WEIGHT = 1000000;
  uint8 private constant MIN_PRECISION = 32;
  uint8 private constant MAX_PRECISION = 127;

  /**
    The values below depend on MAX_PRECISION. If you choose to change it:
    Apply the same change in file 'PrintIntScalingFactors.py', run it and paste the results below.
  */
  uint256 private constant FIXED_1 = 0x080000000000000000000000000000000;
  uint256 private constant FIXED_2 = 0x100000000000000000000000000000000;
  uint256 private constant MAX_NUM = 0x200000000000000000000000000000000;

  /**
      Auto-generated via 'PrintLn2ScalingFactors.py'
  */
  uint256 private constant LN2_NUMERATOR   = 0x3f80fe03f80fe03f80fe03f80fe03f8;
  uint256 private constant LN2_DENOMINATOR = 0x5b9de1d10bf4103d647b0955897ba80;

  /**
      Auto-generated via 'PrintFunctionOptimalLog.py' and 'PrintFunctionOptimalExp.py'
  */
  uint256 private constant OPT_LOG_MAX_VAL =
  0x15bf0a8b1457695355fb8ac404e7a79e3;
  uint256 private constant OPT_EXP_MAX_VAL =
  0x800000000000000000000000000000000;

  /**
    The values below depend on MIN_PRECISION and MAX_PRECISION. If you choose to change either one of them:
    Apply the same change in file 'PrintFunctionBancorFormula.py', run it and paste the results below.
  */
  uint256[128] private maxExpArray;
  constructor() public {
//  maxExpArray[0] = 0x6bffffffffffffffffffffffffffffffff;
//  maxExpArray[1] = 0x67ffffffffffffffffffffffffffffffff;
//  maxExpArray[2] = 0x637fffffffffffffffffffffffffffffff;
//  maxExpArray[3] = 0x5f6fffffffffffffffffffffffffffffff;
//  maxExpArray[4] = 0x5b77ffffffffffffffffffffffffffffff;
//  maxExpArray[5] = 0x57b3ffffffffffffffffffffffffffffff;
//  maxExpArray[6] = 0x5419ffffffffffffffffffffffffffffff;
//  maxExpArray[7] = 0x50a2ffffffffffffffffffffffffffffff;
//  maxExpArray[8] = 0x4d517fffffffffffffffffffffffffffff;
//  maxExpArray[9] = 0x4a233fffffffffffffffffffffffffffff;
//  maxExpArray[10] = 0x47165fffffffffffffffffffffffffffff;
//  maxExpArray[11] = 0x4429afffffffffffffffffffffffffffff;
//  maxExpArray[12] = 0x415bc7ffffffffffffffffffffffffffff;
//  maxExpArray[13] = 0x3eab73ffffffffffffffffffffffffffff;
//  maxExpArray[14] = 0x3c1771ffffffffffffffffffffffffffff;
//  maxExpArray[15] = 0x399e96ffffffffffffffffffffffffffff;
//  maxExpArray[16] = 0x373fc47fffffffffffffffffffffffffff;
//  maxExpArray[17] = 0x34f9e8ffffffffffffffffffffffffffff;
//  maxExpArray[18] = 0x32cbfd5fffffffffffffffffffffffffff;
//  maxExpArray[19] = 0x30b5057fffffffffffffffffffffffffff;
//  maxExpArray[20] = 0x2eb40f9fffffffffffffffffffffffffff;
//  maxExpArray[21] = 0x2cc8340fffffffffffffffffffffffffff;
//  maxExpArray[22] = 0x2af09481ffffffffffffffffffffffffff;
//  maxExpArray[23] = 0x292c5bddffffffffffffffffffffffffff;
//  maxExpArray[24] = 0x277abdcdffffffffffffffffffffffffff;
//  maxExpArray[25] = 0x25daf6657fffffffffffffffffffffffff;
//  maxExpArray[26] = 0x244c49c65fffffffffffffffffffffffff;
//  maxExpArray[27] = 0x22ce03cd5fffffffffffffffffffffffff;
//  maxExpArray[28] = 0x215f77c047ffffffffffffffffffffffff;
//  maxExpArray[29] = 0x1fffffffffffffffffffffffffffffffff;
//  maxExpArray[30] = 0x1eaefdbdabffffffffffffffffffffffff;
//  maxExpArray[31] = 0x1d6bd8b2ebffffffffffffffffffffffff;
    maxExpArray[32] = 0x1c35fedd14ffffffffffffffffffffffff;
    maxExpArray[33] = 0x1b0ce43b323fffffffffffffffffffffff;
    maxExpArray[34] = 0x19f0028ec1ffffffffffffffffffffffff;
    maxExpArray[35] = 0x18ded91f0e7fffffffffffffffffffffff;
    maxExpArray[36] = 0x17d8ec7f0417ffffffffffffffffffffff;
    maxExpArray[37] = 0x16ddc6556cdbffffffffffffffffffffff;
    maxExpArray[38] = 0x15ecf52776a1ffffffffffffffffffffff;
    maxExpArray[39] = 0x15060c256cb2ffffffffffffffffffffff;
    maxExpArray[40] = 0x1428a2f98d72ffffffffffffffffffffff;
    maxExpArray[41] = 0x13545598e5c23fffffffffffffffffffff;
    maxExpArray[42] = 0x1288c4161ce1dfffffffffffffffffffff;
    maxExpArray[43] = 0x11c592761c666fffffffffffffffffffff;
    maxExpArray[44] = 0x110a688680a757ffffffffffffffffffff;
    maxExpArray[45] = 0x1056f1b5bedf77ffffffffffffffffffff;
    maxExpArray[46] = 0x0faadceceeff8bffffffffffffffffffff;
    maxExpArray[47] = 0x0f05dc6b27edadffffffffffffffffffff;
    maxExpArray[48] = 0x0e67a5a25da4107fffffffffffffffffff;
    maxExpArray[49] = 0x0dcff115b14eedffffffffffffffffffff;
    maxExpArray[50] = 0x0d3e7a392431239fffffffffffffffffff;
    maxExpArray[51] = 0x0cb2ff529eb71e4fffffffffffffffffff;
    maxExpArray[52] = 0x0c2d415c3db974afffffffffffffffffff;
    maxExpArray[53] = 0x0bad03e7d883f69bffffffffffffffffff;
    maxExpArray[54] = 0x0b320d03b2c343d5ffffffffffffffffff;
    maxExpArray[55] = 0x0abc25204e02828dffffffffffffffffff;
    maxExpArray[56] = 0x0a4b16f74ee4bb207fffffffffffffffff;
    maxExpArray[57] = 0x09deaf736ac1f569ffffffffffffffffff;
    maxExpArray[58] = 0x0976bd9952c7aa957fffffffffffffffff;
    maxExpArray[59] = 0x09131271922eaa606fffffffffffffffff;
    maxExpArray[60] = 0x08b380f3558668c46fffffffffffffffff;
    maxExpArray[61] = 0x0857ddf0117efa215bffffffffffffffff;
    maxExpArray[62] = 0x07ffffffffffffffffffffffffffffffff;
    maxExpArray[63] = 0x07abbf6f6abb9d087fffffffffffffffff;
    maxExpArray[64] = 0x075af62cbac95f7dfa7fffffffffffffff;
    maxExpArray[65] = 0x070d7fb7452e187ac13fffffffffffffff;
    maxExpArray[66] = 0x06c3390ecc8af379295fffffffffffffff;
    maxExpArray[67] = 0x067c00a3b07ffc01fd6fffffffffffffff;
    maxExpArray[68] = 0x0637b647c39cbb9d3d27ffffffffffffff;
    maxExpArray[69] = 0x05f63b1fc104dbd39587ffffffffffffff;
    maxExpArray[70] = 0x05b771955b36e12f7235ffffffffffffff;
    maxExpArray[71] = 0x057b3d49dda84556d6f6ffffffffffffff;
    maxExpArray[72] = 0x054183095b2c8ececf30ffffffffffffff;
    maxExpArray[73] = 0x050a28be635ca2b888f77fffffffffffff;
    maxExpArray[74] = 0x04d5156639708c9db33c3fffffffffffff;
    maxExpArray[75] = 0x04a23105873875bd52dfdfffffffffffff;
    maxExpArray[76] = 0x0471649d87199aa990756fffffffffffff;
    maxExpArray[77] = 0x04429a21a029d4c1457cfbffffffffffff;
    maxExpArray[78] = 0x0415bc6d6fb7dd71af2cb3ffffffffffff;
    maxExpArray[79] = 0x03eab73b3bbfe282243ce1ffffffffffff;
    maxExpArray[80] = 0x03c1771ac9fb6b4c18e229ffffffffffff;
    maxExpArray[81] = 0x0399e96897690418f785257fffffffffff;
    maxExpArray[82] = 0x0373fc456c53bb779bf0ea9fffffffffff;
    maxExpArray[83] = 0x034f9e8e490c48e67e6ab8bfffffffffff;
    maxExpArray[84] = 0x032cbfd4a7adc790560b3337ffffffffff;
    maxExpArray[85] = 0x030b50570f6e5d2acca94613ffffffffff;
    maxExpArray[86] = 0x02eb40f9f620fda6b56c2861ffffffffff;
    maxExpArray[87] = 0x02cc8340ecb0d0f520a6af58ffffffffff;
    maxExpArray[88] = 0x02af09481380a0a35cf1ba02ffffffffff;
    maxExpArray[89] = 0x0292c5bdd3b92ec810287b1b3fffffffff;
    maxExpArray[90] = 0x0277abdcdab07d5a77ac6d6b9fffffffff;
    maxExpArray[91] = 0x025daf6654b1eaa55fd64df5efffffffff;
    maxExpArray[92] = 0x0244c49c648baa98192dce88b7ffffffff;
    maxExpArray[93] = 0x022ce03cd5619a311b2471268bffffffff;
    maxExpArray[94] = 0x0215f77c045fbe885654a44a0fffffffff;
    maxExpArray[95] = 0x01ffffffffffffffffffffffffffffffff;
    maxExpArray[96] = 0x01eaefdbdaaee7421fc4d3ede5ffffffff;
    maxExpArray[97] = 0x01d6bd8b2eb257df7e8ca57b09bfffffff;
    maxExpArray[98] = 0x01c35fedd14b861eb0443f7f133fffffff;
    maxExpArray[99] = 0x01b0ce43b322bcde4a56e8ada5afffffff;
    maxExpArray[100] = 0x019f0028ec1fff007f5a195a39dfffffff;
    maxExpArray[101] = 0x018ded91f0e72ee74f49b15ba527ffffff;
    maxExpArray[102] = 0x017d8ec7f04136f4e5615fd41a63ffffff;
    maxExpArray[103] = 0x016ddc6556cdb84bdc8d12d22e6fffffff;
    maxExpArray[104] = 0x015ecf52776a1155b5bd8395814f7fffff;
    maxExpArray[105] = 0x015060c256cb23b3b3cc3754cf40ffffff;
    maxExpArray[106] = 0x01428a2f98d728ae223ddab715be3fffff;
    maxExpArray[107] = 0x013545598e5c23276ccf0ede68034fffff;
    maxExpArray[108] = 0x01288c4161ce1d6f54b7f61081194fffff;
    maxExpArray[109] = 0x011c592761c666aa641d5a01a40f17ffff;
    maxExpArray[110] = 0x0110a688680a7530515f3e6e6cfdcdffff;
    maxExpArray[111] = 0x01056f1b5bedf75c6bcb2ce8aed428ffff;
    maxExpArray[112] = 0x00faadceceeff8a0890f3875f008277fff;
    maxExpArray[113] = 0x00f05dc6b27edad306388a600f6ba0bfff;
    maxExpArray[114] = 0x00e67a5a25da41063de1495d5b18cdbfff;
    maxExpArray[115] = 0x00dcff115b14eedde6fc3aa5353f2e4fff;
    maxExpArray[116] = 0x00d3e7a3924312399f9aae2e0f868f8fff;
    maxExpArray[117] = 0x00cb2ff529eb71e41582cccd5a1ee26fff;
    maxExpArray[118] = 0x00c2d415c3db974ab32a51840c0b67edff;
    maxExpArray[119] = 0x00bad03e7d883f69ad5b0a186184e06bff;
    maxExpArray[120] = 0x00b320d03b2c343d4829abd6075f0cc5ff;
    maxExpArray[121] = 0x00abc25204e02828d73c6e80bcdb1a95bf;
    maxExpArray[122] = 0x00a4b16f74ee4bb2040a1ec6c15fbbf2df;
    maxExpArray[123] = 0x009deaf736ac1f569deb1b5ae3f36c130f;
    maxExpArray[124] = 0x00976bd9952c7aa957f5937d790ef65037;
    maxExpArray[125] = 0x009131271922eaa6064b73a22d0bd4f2bf;
    maxExpArray[126] = 0x008b380f3558668c46c91c49a2f8e967b9;
    maxExpArray[127] = 0x00857ddf0117efa215952912839f6473e6;
  }

  /**
    General Description:
        Determine a value of precision.
        Calculate an integer approximation of (_baseN / _baseD) ^ (_expN / _expD) * 2 ^ precision.
        Return the result along with the precision used.
     Detailed Description:
        Instead of calculating "base ^ exp", we calculate "e ^ (log(base) * exp)".
        The value of "log(base)" is represented with an integer slightly smaller than "log(base) * 2 ^ precision".
        The larger "precision" is, the more accurately this value represents the real value.
        However, the larger "precision" is, the more bits are required in order to store this value.
        And the exponentiation function, which takes "x" and calculates "e ^ x", is limited to a maximum exponent (maximum value of "x").
        This maximum exponent depends on the "precision" used, and it is given by "maxExpArray[precision] >> (MAX_PRECISION - precision)".
        Hence we need to determine the highest precision which can be used for the given input, before calling the exponentiation function.
        This allows us to compute "base ^ exp" with maximum accuracy and without exceeding 256 bits in any of the intermediate computations.
        This functions assumes that "_expN < 2 ^ 256 / log(MAX_NUM - 1)", otherwise the multiplication should be replaced with a "safeMul".
  */
  function power(
    uint256 _baseN,
    uint256 _baseD,
    uint32 _expN,
    uint32 _expD
  ) internal view returns (uint256, uint8)
  {
    require(_baseN < MAX_NUM, "baseN exceeds max value.");
    require(_baseN >= _baseD, "Bases < 1 are not supported.");

    uint256 baseLog;
    uint256 base = _baseN * FIXED_1 / _baseD;
    if (base < OPT_LOG_MAX_VAL) {
      baseLog = optimalLog(base);
    } else {
      baseLog = generalLog(base);
    }

    uint256 baseLogTimesExp = baseLog * _expN / _expD;
    if (baseLogTimesExp < OPT_EXP_MAX_VAL) {
      return (optimalExp(baseLogTimesExp), MAX_PRECISION);
    } else {
      uint8 precision = findPositionInMaxExpArray(baseLogTimesExp);
      return (generalExp(baseLogTimesExp >> (MAX_PRECISION - precision), precision), precision);
    }
  }

  /**
      Compute log(x / FIXED_1) * FIXED_1.
      This functions assumes that "x >= FIXED_1", because the output would be negative otherwise.
  */
  function generalLog(uint256 _x) internal pure returns (uint256) {
    uint256 res = 0;
    uint256 x = _x;

    // If x >= 2, then we compute the integer part of log2(x), which is larger than 0.
    if (x >= FIXED_2) {
      uint8 count = floorLog2(x / FIXED_1);
      x >>= count; // now x < 2
      res = count * FIXED_1;
    }

    // If x > 1, then we compute the fraction part of log2(x), which is larger than 0.
    if (x > FIXED_1) {
      for (uint8 i = MAX_PRECISION; i > 0; --i) {
        x = (x * x) / FIXED_1; // now 1 < x < 4
        if (x >= FIXED_2) {
          x >>= 1; // now 1 < x < 2
          res += ONE << (i - 1);
        }
      }
    }

    return res * LN2_NUMERATOR / LN2_DENOMINATOR;
  }

  /**
    Compute the largest integer smaller than or equal to the binary logarithm of the input.
  */
  function floorLog2(uint256 _n) internal pure returns (uint8) {
    uint8 res = 0;
    uint256 n = _n;

    if (n < 256) {
      // At most 8 iterations
      while (n > 1) {
        n >>= 1;
        res += 1;
      }
    } else {
      // Exactly 8 iterations
      for (uint8 s = 128; s > 0; s >>= 1) {
        if (n >= (ONE << s)) {
          n >>= s;
          res |= s;
        }
      }
    }

    return res;
  }

  /**
      The global "maxExpArray" is sorted in descending order, and therefore the following statements are equivalent:
      - This function finds the position of [the smallest value in "maxExpArray" larger than or equal to "x"]
      - This function finds the highest position of [a value in "maxExpArray" larger than or equal to "x"]
  */
  function findPositionInMaxExpArray(uint256 _x)
  internal view returns (uint8)
  {
    uint8 lo = MIN_PRECISION;
    uint8 hi = MAX_PRECISION;

    while (lo + 1 < hi) {
      uint8 mid = (lo + hi) / 2;
      if (maxExpArray[mid] >= _x)
        lo = mid;
      else
        hi = mid;
    }

    if (maxExpArray[hi] >= _x)
      return hi;
    if (maxExpArray[lo] >= _x)
      return lo;

    assert(false);
    return 0;
  }

  /* solium-disable */
  /**
       This function can be auto-generated by the script 'PrintFunctionGeneralExp.py'.
       It approximates "e ^ x" via maclaurin summation: "(x^0)/0! + (x^1)/1! + ... + (x^n)/n!".
       It returns "e ^ (x / 2 ^ precision) * 2 ^ precision", that is, the result is upshifted for accuracy.
       The global "maxExpArray" maps each "precision" to "((maximumExponent + 1) << (MAX_PRECISION - precision)) - 1".
       The maximum permitted value for "x" is therefore given by "maxExpArray[precision] >> (MAX_PRECISION - precision)".
   */
   function generalExp(uint256 _x, uint8 _precision) internal pure returns (uint256) {
       uint256 xi = _x;
       uint256 res = 0;

       xi = (xi * _x) >> _precision; res += xi * 0x3442c4e6074a82f1797f72ac0000000; // add x^02 * (33! / 02!)
       xi = (xi * _x) >> _precision; res += xi * 0x116b96f757c380fb287fd0e40000000; // add x^03 * (33! / 03!)
       xi = (xi * _x) >> _precision; res += xi * 0x045ae5bdd5f0e03eca1ff4390000000; // add x^04 * (33! / 04!)
       xi = (xi * _x) >> _precision; res += xi * 0x00defabf91302cd95b9ffda50000000; // add x^05 * (33! / 05!)
       xi = (xi * _x) >> _precision; res += xi * 0x002529ca9832b22439efff9b8000000; // add x^06 * (33! / 06!)
       xi = (xi * _x) >> _precision; res += xi * 0x00054f1cf12bd04e516b6da88000000; // add x^07 * (33! / 07!)
       xi = (xi * _x) >> _precision; res += xi * 0x0000a9e39e257a09ca2d6db51000000; // add x^08 * (33! / 08!)
       xi = (xi * _x) >> _precision; res += xi * 0x000012e066e7b839fa050c309000000; // add x^09 * (33! / 09!)
       xi = (xi * _x) >> _precision; res += xi * 0x000001e33d7d926c329a1ad1a800000; // add x^10 * (33! / 10!)
       xi = (xi * _x) >> _precision; res += xi * 0x0000002bee513bdb4a6b19b5f800000; // add x^11 * (33! / 11!)
       xi = (xi * _x) >> _precision; res += xi * 0x00000003a9316fa79b88eccf2a00000; // add x^12 * (33! / 12!)
       xi = (xi * _x) >> _precision; res += xi * 0x0000000048177ebe1fa812375200000; // add x^13 * (33! / 13!)
       xi = (xi * _x) >> _precision; res += xi * 0x0000000005263fe90242dcbacf00000; // add x^14 * (33! / 14!)
       xi = (xi * _x) >> _precision; res += xi * 0x000000000057e22099c030d94100000; // add x^15 * (33! / 15!)
       xi = (xi * _x) >> _precision; res += xi * 0x0000000000057e22099c030d9410000; // add x^16 * (33! / 16!)
       xi = (xi * _x) >> _precision; res += xi * 0x00000000000052b6b54569976310000; // add x^17 * (33! / 17!)
       xi = (xi * _x) >> _precision; res += xi * 0x00000000000004985f67696bf748000; // add x^18 * (33! / 18!)
       xi = (xi * _x) >> _precision; res += xi * 0x000000000000003dea12ea99e498000; // add x^19 * (33! / 19!)
       xi = (xi * _x) >> _precision; res += xi * 0x00000000000000031880f2214b6e000; // add x^20 * (33! / 20!)
       xi = (xi * _x) >> _precision; res += xi * 0x000000000000000025bcff56eb36000; // add x^21 * (33! / 21!)
       xi = (xi * _x) >> _precision; res += xi * 0x000000000000000001b722e10ab1000; // add x^22 * (33! / 22!)
       xi = (xi * _x) >> _precision; res += xi * 0x0000000000000000001317c70077000; // add x^23 * (33! / 23!)
       xi = (xi * _x) >> _precision; res += xi * 0x00000000000000000000cba84aafa00; // add x^24 * (33! / 24!)
       xi = (xi * _x) >> _precision; res += xi * 0x00000000000000000000082573a0a00; // add x^25 * (33! / 25!)
       xi = (xi * _x) >> _precision; res += xi * 0x00000000000000000000005035ad900; // add x^26 * (33! / 26!)
       xi = (xi * _x) >> _precision; res += xi * 0x000000000000000000000002f881b00; // add x^27 * (33! / 27!)
       xi = (xi * _x) >> _precision; res += xi * 0x0000000000000000000000001b29340; // add x^28 * (33! / 28!)
       xi = (xi * _x) >> _precision; res += xi * 0x00000000000000000000000000efc40; // add x^29 * (33! / 29!)
       xi = (xi * _x) >> _precision; res += xi * 0x0000000000000000000000000007fe0; // add x^30 * (33! / 30!)
       xi = (xi * _x) >> _precision; res += xi * 0x0000000000000000000000000000420; // add x^31 * (33! / 31!)
       xi = (xi * _x) >> _precision; res += xi * 0x0000000000000000000000000000021; // add x^32 * (33! / 32!)
       xi = (xi * _x) >> _precision; res += xi * 0x0000000000000000000000000000001; // add x^33 * (33! / 33!)

       return res / 0x688589cc0e9505e2f2fee5580000000 + _x + (ONE << _precision); // divide by 33! and then add x^1 / 1! + x^0 / 0!
   }

   /**
       Return log(x / FIXED_1) * FIXED_1
       Input range: FIXED_1 <= x <= LOG_EXP_MAX_VAL - 1
       Auto-generated via 'PrintFunctionOptimalLog.py'
   */
   function optimalLog(uint256 x) internal pure returns (uint256) {
       uint256 res = 0;

       uint256 y;
       uint256 z;
       uint256 w;

       if (x >= 0xd3094c70f034de4b96ff7d5b6f99fcd8) {res += 0x40000000000000000000000000000000; x = x * FIXED_1 / 0xd3094c70f034de4b96ff7d5b6f99fcd8;}
       if (x >= 0xa45af1e1f40c333b3de1db4dd55f29a7) {res += 0x20000000000000000000000000000000; x = x * FIXED_1 / 0xa45af1e1f40c333b3de1db4dd55f29a7;}
       if (x >= 0x910b022db7ae67ce76b441c27035c6a1) {res += 0x10000000000000000000000000000000; x = x * FIXED_1 / 0x910b022db7ae67ce76b441c27035c6a1;}
       if (x >= 0x88415abbe9a76bead8d00cf112e4d4a8) {res += 0x08000000000000000000000000000000; x = x * FIXED_1 / 0x88415abbe9a76bead8d00cf112e4d4a8;}
       if (x >= 0x84102b00893f64c705e841d5d4064bd3) {res += 0x04000000000000000000000000000000; x = x * FIXED_1 / 0x84102b00893f64c705e841d5d4064bd3;}
       if (x >= 0x8204055aaef1c8bd5c3259f4822735a2) {res += 0x02000000000000000000000000000000; x = x * FIXED_1 / 0x8204055aaef1c8bd5c3259f4822735a2;}
       if (x >= 0x810100ab00222d861931c15e39b44e99) {res += 0x01000000000000000000000000000000; x = x * FIXED_1 / 0x810100ab00222d861931c15e39b44e99;}
       if (x >= 0x808040155aabbbe9451521693554f733) {res += 0x00800000000000000000000000000000; x = x * FIXED_1 / 0x808040155aabbbe9451521693554f733;}

       z = y = x - FIXED_1;
       w = y * y / FIXED_1;
       res += z * (0x100000000000000000000000000000000 - y) / 0x100000000000000000000000000000000; z = z * w / FIXED_1;
       res += z * (0x0aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa - y) / 0x200000000000000000000000000000000; z = z * w / FIXED_1;
       res += z * (0x099999999999999999999999999999999 - y) / 0x300000000000000000000000000000000; z = z * w / FIXED_1;
       res += z * (0x092492492492492492492492492492492 - y) / 0x400000000000000000000000000000000; z = z * w / FIXED_1;
       res += z * (0x08e38e38e38e38e38e38e38e38e38e38e - y) / 0x500000000000000000000000000000000; z = z * w / FIXED_1;
       res += z * (0x08ba2e8ba2e8ba2e8ba2e8ba2e8ba2e8b - y) / 0x600000000000000000000000000000000; z = z * w / FIXED_1;
       res += z * (0x089d89d89d89d89d89d89d89d89d89d89 - y) / 0x700000000000000000000000000000000; z = z * w / FIXED_1;
       res += z * (0x088888888888888888888888888888888 - y) / 0x800000000000000000000000000000000;

       return res;
   }

   /**
       Return e ^ (x / FIXED_1) * FIXED_1
       Input range: 0 <= x <= OPT_EXP_MAX_VAL - 1
       Auto-generated via 'PrintFunctionOptimalExp.py'
   */
   function optimalExp(uint256 x) internal pure returns (uint256) {
       uint256 res = 0;

       uint256 y;
       uint256 z;

       z = y = x % 0x10000000000000000000000000000000;
       z = z * y / FIXED_1; res += z * 0x10e1b3be415a0000; // add y^02 * (20! / 02!)
       z = z * y / FIXED_1; res += z * 0x05a0913f6b1e0000; // add y^03 * (20! / 03!)
       z = z * y / FIXED_1; res += z * 0x0168244fdac78000; // add y^04 * (20! / 04!)
       z = z * y / FIXED_1; res += z * 0x004807432bc18000; // add y^05 * (20! / 05!)
       z = z * y / FIXED_1; res += z * 0x000c0135dca04000; // add y^06 * (20! / 06!)
       z = z * y / FIXED_1; res += z * 0x0001b707b1cdc000; // add y^07 * (20! / 07!)
       z = z * y / FIXED_1; res += z * 0x000036e0f639b800; // add y^08 * (20! / 08!)
       z = z * y / FIXED_1; res += z * 0x00000618fee9f800; // add y^09 * (20! / 09!)
       z = z * y / FIXED_1; res += z * 0x0000009c197dcc00; // add y^10 * (20! / 10!)
       z = z * y / FIXED_1; res += z * 0x0000000e30dce400; // add y^11 * (20! / 11!)
       z = z * y / FIXED_1; res += z * 0x000000012ebd1300; // add y^12 * (20! / 12!)
       z = z * y / FIXED_1; res += z * 0x0000000017499f00; // add y^13 * (20! / 13!)
       z = z * y / FIXED_1; res += z * 0x0000000001a9d480; // add y^14 * (20! / 14!)
       z = z * y / FIXED_1; res += z * 0x00000000001c6380; // add y^15 * (20! / 15!)
       z = z * y / FIXED_1; res += z * 0x000000000001c638; // add y^16 * (20! / 16!)
       z = z * y / FIXED_1; res += z * 0x0000000000001ab8; // add y^17 * (20! / 17!)
       z = z * y / FIXED_1; res += z * 0x000000000000017c; // add y^18 * (20! / 18!)
       z = z * y / FIXED_1; res += z * 0x0000000000000014; // add y^19 * (20! / 19!)
       z = z * y / FIXED_1; res += z * 0x0000000000000001; // add y^20 * (20! / 20!)
       res = res / 0x21c3677c82b40000 + y + FIXED_1; // divide by 20! and then add y^1 / 1! + y^0 / 0!

       if ((x & 0x010000000000000000000000000000000) != 0) res = res * 0x1c3d6a24ed82218787d624d3e5eba95f9 / 0x18ebef9eac820ae8682b9793ac6d1e776;
       if ((x & 0x020000000000000000000000000000000) != 0) res = res * 0x18ebef9eac820ae8682b9793ac6d1e778 / 0x1368b2fc6f9609fe7aceb46aa619baed4;
       if ((x & 0x040000000000000000000000000000000) != 0) res = res * 0x1368b2fc6f9609fe7aceb46aa619baed5 / 0x0bc5ab1b16779be3575bd8f0520a9f21f;
       if ((x & 0x080000000000000000000000000000000) != 0) res = res * 0x0bc5ab1b16779be3575bd8f0520a9f21e / 0x0454aaa8efe072e7f6ddbab84b40a55c9;
       if ((x & 0x100000000000000000000000000000000) != 0) res = res * 0x0454aaa8efe072e7f6ddbab84b40a55c5 / 0x00960aadc109e7a3bf4578099615711ea;
       if ((x & 0x200000000000000000000000000000000) != 0) res = res * 0x00960aadc109e7a3bf4578099615711d7 / 0x0002bf84208204f5977f9a8cf01fdce3d;
       if ((x & 0x400000000000000000000000000000000) != 0) res = res * 0x0002bf84208204f5977f9a8cf01fdc307 / 0x0000003c6ab775dd0b95b4cbee7e65d11;

       return res;
   }
   /* solium-enable */
}

// File: contracts\BancorBondingCurve.sol

pragma solidity ^0.5.2;



/**
* @title Bancor formula by Bancor
*
* Licensed to the Apache Software Foundation (ASF) under one or more contributor license agreements;
* and to You under the Apache License, Version 2.0. "
*/
contract BancorBondingCurve is Power {
   using SafeMath for uint256;
   uint32 private constant MAX_RESERVE_RATIO = 1000000;

   /**
   * @dev given a continuous token supply, reserve token balance, reserve ratio, and a deposit amount (in the reserve token),
   * calculates the return for a given conversion (in the continuous token)
   *
   * Formula:
   * Return = _supply * ((1 + _depositAmount / _reserveBalance) ^ (_reserveRatio / MAX_RESERVE_RATIO) - 1)
   *
   * @param _supply              continuous token total supply
   * @param _reserveBalance    total reserve token balance
   * @param _reserveRatio     reserve ratio, represented in ppm, 1-1000000
   * @param _depositAmount       deposit amount, in reserve token
   *
   *  @return purchase return amount
  */
  function calculatePurchaseReturn(
    uint256 _supply,
    uint256 _reserveBalance,
    uint32 _reserveRatio,
    uint256 _depositAmount) public view returns (uint256)
  {
    // validate input
    require(_supply > 0 && _reserveBalance > 0 && _reserveRatio > 0 && _reserveRatio <= MAX_RESERVE_RATIO);
     // special case for 0 deposit amount
    if (_depositAmount == 0) {
      return 0;
    }
     // special case if the ratio = 100%
    if (_reserveRatio == MAX_RESERVE_RATIO) {
      return _supply.mul(_depositAmount).div(_reserveBalance);
    }
     uint256 result;
    uint8 precision;
    uint256 baseN = _depositAmount.add(_reserveBalance);
    (result, precision) = power(
      baseN, _reserveBalance, _reserveRatio, MAX_RESERVE_RATIO
    );
    uint256 newTokenSupply = _supply.mul(result) >> precision;
    return newTokenSupply - _supply;
  }
   /**
   * @dev given a continuous token supply, reserve token balance, reserve ratio and a sell amount (in the continuous token),
   * calculates the return for a given conversion (in the reserve token)
   *
   * Formula:
   * Return = _reserveBalance * (1 - (1 - _sellAmount / _supply) ^ (1 / (_reserveRatio / MAX_RESERVE_RATIO)))
   *
   * @param _supply              continuous token total supply
   * @param _reserveBalance    total reserve token balance
   * @param _reserveRatio     constant reserve ratio, represented in ppm, 1-1000000
   * @param _sellAmount          sell amount, in the continuous token itself
   *
   * @return sale return amount
  */
  function calculateSaleReturn(
    uint256 _supply,
    uint256 _reserveBalance,
    uint32 _reserveRatio,
    uint256 _sellAmount) public view returns (uint256)
  {
    // validate input
    require(_supply > 0 && _reserveBalance > 0 && _reserveRatio > 0 && _reserveRatio <= MAX_RESERVE_RATIO && _sellAmount <= _supply);
     // special case for 0 sell amount
    if (_sellAmount == 0) {
      return 0;
    }
     // special case for selling the entire supply
    if (_sellAmount == _supply) {
      return _reserveBalance;
    }
     // special case if the ratio = 100%
    if (_reserveRatio == MAX_RESERVE_RATIO) {
      return _reserveBalance.mul(_sellAmount).div(_supply);
    }
     uint256 result;
    uint8 precision;
    uint256 baseD = _supply - _sellAmount;
    (result, precision) = power(
      _supply, baseD, MAX_RESERVE_RATIO, _reserveRatio
    );
    uint256 oldBalance = _reserveBalance.mul(result);
    uint256 newBalance = _reserveBalance << precision;
    return oldBalance.sub(newBalance).div(result);
  }
}

// File: contracts\ContinuousToken.sol

pragma solidity ^0.5.2;





contract ContinuousToken is BancorBondingCurve, Ownable, ERC20 {
    
    using SafeMath for uint256;

    uint256 public scale = 10**18;
    uint256 public reserveBalance = 10*scale;
    uint256 public reserveRatio = 500000;

    constructor() public {
        _mint(msg.sender, 1*scale);
    }

    function mint(address reciever, uint value) public payable {
        require(value > 0, "Must send ether to buy tokens.");
        _continuousMint(reciever, value);
    }

    function burn(uint256 _amount) public {
        uint256 returnAmount = _continuousBurn(_amount);
        msg.sender.transfer(returnAmount);
    }

    function calculateContinuousMintReturn(uint256 _amount)
        public view returns (uint256 mintAmount)
    {
        return calculatePurchaseReturn(totalSupply(), reserveBalance, uint32(reserveRatio), _amount);
    }

    function calculateContinuousBurnReturn(uint256 _amount)
        public view returns (uint256 burnAmount)
    {
        return calculateSaleReturn(totalSupply(), reserveBalance, uint32(reserveRatio), _amount);
    }

    function _continuousMint(address reciever, uint value)
        internal returns (uint256)
    {
        require(value > 0, "Deposit must be non-zero.");

        uint256 amount = calculateContinuousMintReturn(value);
        _mint(reciever, amount);
        reserveBalance = reserveBalance.add(value);
        return amount;
    }

    function _continuousBurn(uint256 _amount)
        internal returns (uint256)
    {
        require(_amount > 0, "Amount must be non-zero.");
        require(balanceOf(msg.sender) >= _amount, "Insufficient tokens to burn.");

        uint256 reimburseAmount = calculateContinuousBurnReturn(_amount);
        reserveBalance = reserveBalance.sub(reimburseAmount);
        _burn(msg.sender, _amount);
        return reimburseAmount;
    }
}

// File: contracts\SpaceMiners.sol

pragma solidity ^0.5.2;

// GAME



// TOKEN


contract SpaceMiners is Ownable, ContinuousToken {

  using SafeMath for uint;

  uint public constant PRICE_TO_MINE = 20 finney;
  uint public constant PLANET_CAPACITY = 10;
  uint public constant NUM_WINNERS = 3;
  uint constant OWNER_FEE_PERCENT = 5;
  address[] miners = new address[](PLANET_CAPACITY);
  uint public planetPopulation = 0;
  uint ownerHoldings = 1;

  string public constant name = "Kerium Crystals";
  string public constant symbol = "KMC";
  uint8 public constant decimals = 18;

  function getNumUsersMinersOnPlanet(address miner) public view returns (uint) {
    uint count = 0;
    for (uint i = 0; i < planetPopulation; i++) {
      if (miners[i] == miner) {
        count++;
      }
    }
    return count;
  }

  function sendSingleMinerToPlanet(address miner) internal {
    miners[planetPopulation] = miner;
    planetPopulation = planetPopulation.add(1);
    if (planetPopulation == PLANET_CAPACITY) {
      rewardMiners();
      planetPopulation = 0;
    }
  }

  function sendMinersToPlanet(uint numMiners) public payable {
    require(msg.value >= numMiners * PRICE_TO_MINE, "Not enough paid");
    require(planetPopulation < PLANET_CAPACITY, "Planet is full");
    mint(msg.sender, numMiners);
    for (uint i = 0; i < numMiners; i++) {
      sendSingleMinerToPlanet(msg.sender);
    }
  }

  function percentOfValue(uint percent, uint value) pure internal returns (uint) {
    return (value.mul(percent)).div(100);
  }

  function getRandom(uint cap) view internal returns (uint) {
    return uint256(keccak256(abi.encodePacked(block.timestamp, block.difficulty))) % cap;
  }

  function rewardMiners() internal {
    // First take OWNER_FEE_PERCENT
    uint roundEarnings = PRICE_TO_MINE * PLANET_CAPACITY;
    uint ownerFee = percentOfValue(OWNER_FEE_PERCENT, roundEarnings);
    ownerHoldings = ownerHoldings.add(ownerFee);
    roundEarnings = roundEarnings.sub(ownerFee);
    uint rewardAmount = roundEarnings.div(NUM_WINNERS);
    for (uint i = 0; i < NUM_WINNERS; i++) {
      uint rnd = getRandom(PLANET_CAPACITY);
      mint(miners[rnd], rewardAmount);
    }
  }

  function cashOutOwnerFee() public payable onlyOwner {
    require(ownerHoldings > 1);
    msg.sender.transfer(ownerHoldings - 1);
    ownerHoldings = 1;
  }

  function() external payable {}

}