library SafeMath {
		/**
		* @dev Substracts two numbers, throws on overflow (i.e. if subtrahend is greater than minuend).
		*/
		function sub(uint a, uint b) internal pure returns (uint) {
			assert(b <= a);
			return a - b;
		}

		/**
		* @dev Adds two numbers, throws on overflow.
		*/
		function add(uint a, uint b) internal pure returns (uint) {
			uint c = a + b;
			assert(c >= a);
			return c;
		}
		/**
		* @dev Multiplies two numbers, throws on overflow.
		*/
		function mul(uint a, uint b) internal pure returns (uint) {
			if (a == 0) {
				return 0;
			}
			uint c = a * b;
			assert(c / a == b);
			return c;
		}

		/**
		* @dev Integer division of two numbers, truncating the quotient.
		*/
		function div(uint a, uint b) internal pure returns (uint) {
			// assert(b > 0); // Solidity automatically throws when dividing by 0
			uint c = a / b;
			// assert(a == b * c + a % b); // There is no case in which this doesn't hold
			return c;
		}


	}
/**
 	 * @title SafeMath
 	 * @dev Math operations with safety checks that throw on error
 	 */
function div(uint a, uint b) internal pure returns (uint) {
	// assert(b > 0); // Solidity automatically throws when dividing by 0
	uint c = a / b;
	// assert(a == b * c + a % b); // There is no case in which this doesn't hold
	return c;
}

/**
 		* @dev Integer division of two numbers, truncating the quotient.
 		*/