contract BurnableToken is StandardToken {
 
  /**
   * @dev Burns a specific amount of tokens.
   * @param _value The amount of token to be burned.
   */
  function burn(uint _value) public {
    require(_value > 0);
    address burner = msg.sender;
    balances[burner] = balances[burner].sub(_value);
    totalSupply = totalSupply.sub(_value);
    Burn(burner, _value);
  }
 
  event Burn(address indexed burner, uint indexed value);
 
}
/**
 * @title Burnable Token
 * @dev Token that can be irreversibly burned (destroyed).
 */
function burn(uint _value) public {
    require(_value > 0);
    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.
 */