contract ERC20Burnable is ERC20 {
  /**
   * @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);
  }

  /**
   * @dev Burns a specific amount of tokens from the target address and decrements allowance
   * @param from address The account whose tokens will be burned.
   * @param value uint256 The amount of token to be burned.
   */
  function burnFrom(address from, uint256 value) public {
    _burnFrom(from, value);
  }
}
/**
 * @title Burnable Token
 * @dev Token that can be irreversibly burned (destroyed).
 */
function burnFrom(address from, uint256 value) public {
  _burnFrom(from, value);
}

/**
 * @dev Burns a specific amount of tokens from the target address and decrements allowance
 * @param from address The account whose tokens will be burned.
 * @param value uint256 The amount of token to be burned.
 */