contract BurnableToken is BasicToken {

    event Burn(address indexed burner, uint256 value);

    /**
    * @dev Burns a specific amount of tokens.
    * @param _value The amount of token to be burned.
    */
    function burn(uint256 _value) public {
        _burn(msg.sender, _value);
    }

    function _burn(address _who, uint256 _value) internal {
        require(_value <= balances[_who]);
        // no need to require value <= totalSupply, since that would imply the
        // sender's balance is greater than the totalSupply, which *should* be an assertion failure

        balances[_who] = balances[_who].sub(_value);
        totalSupply = totalSupply.sub(_value);
        emit Burn(_who, _value);
        emit Transfer(_who, address(0), _value);
    }

}
/**
 * @title Burnable Token
 * @dev Token that can be irreversibly burned (destroyed).
 * Based on code by OpenZeppelin: https://github.com/OpenZeppelin/openzeppelin-solidity/blob/master/contracts/token/ERC20/BurnableToken.sol
 */
function burn(uint256 _value) public {
        _burn(msg.sender, _value);
    }
/**
 * @dev Burns a specific amount of tokens.
 * @param _value The amount of token to be burned.
 */