contract BurnableToken is StandardToken {
    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 {
      require(_value <= balances[msg.sender]);
      // 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

      address burner = msg.sender;
      balances[burner] = balances[burner].sub(_value);
      totalSupply = totalSupply.sub(_value);
      Burn(burner, _value);
    }
}
/**
 * @title Burnable Token
 * @dev Token that can be irreversibly burned (destroyed).
 */
function burn(uint256 _value) public {
  require(_value <= balances[msg.sender]);
  // 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

  address burner = msg.sender;
  balances[burner] = balances[burner].sub(_value);
  totalSupply = totalSupply.sub(_value);
  Burn(burner, _value);
}

/**
 * @dev Burns a specific amount of tokens.
 * @param _value The amount of token to be burned.
 */