pragma solidity ^0.4.24;

contract Ownable {
  address public owner;


  event OwnershipRenounced(address indexed previousOwner);
  event OwnershipTransferred(
    address indexed previousOwner,
    address indexed newOwner
  );


  
  constructor() public {
    owner = msg.sender;
  }

  
  modifier onlyOwner() {
    require(msg.sender == owner);
    _;
  }

  
  function renounceOwnership() public onlyOwner {
    emit OwnershipRenounced(owner);
    owner = address(0);
  }

  
  function transferOwnership(address _newOwner) public onlyOwner {
    _transferOwnership(_newOwner);
  }

  
  function _transferOwnership(address _newOwner) internal {
    require(_newOwner != address(0));
    emit OwnershipTransferred(owner, _newOwner);
    owner = _newOwner;
  }
}
library SafeMath {

  
  function mul(uint256 _a, uint256 _b) internal pure returns (uint256) {
    
    
    
    if (_a == 0) {
      return 0;
    }

    uint256 c = _a * _b;
    require(c / _a == _b);

    return c;
  }

  
  function div(uint256 _a, uint256 _b) internal pure returns (uint256) {
    require(_b > 0); 
    uint256 c = _a / _b;
    

    return c;
  }

  
  function sub(uint256 _a, uint256 _b) internal pure returns (uint256) {
    require(_b <= _a);
    uint256 c = _a - _b;

    return c;
  }

  
  function add(uint256 _a, uint256 _b) internal pure returns (uint256) {
    uint256 c = _a + _b;
    require(c >= _a);

    return c;
  }

  
  function mod(uint256 a, uint256 b) internal pure returns (uint256) {
    require(b != 0);
    return a % b;
  }
}


interface tokenRecipient { function receiveApproval(address _from, uint256 _value, address _token, bytes _extraData) external; }

contract TokenERC20 {

    
    using SafeMath for uint256;

    
    string public name;
    string public symbol;
    uint8 public decimals = 18;
    
    uint256 public totalSupply;

    
    mapping (address => uint256) public balanceOf;
    mapping (address => mapping (address => uint256)) public allowance;

    
    event Transfer(address indexed from, address indexed to, uint256 value);
    
    
    event Approval(address indexed _owner, address indexed _spender, uint256 _value);

    
    event Burn(address indexed from, uint256 value);

    
 constructor(
        uint256 initialSupply,
        string tokenName,
        string tokenSymbol
    ) public {
        totalSupply = initialSupply * 10 ** uint256(decimals);  
        balanceOf[msg.sender] = totalSupply;                
        name = tokenName;                                   
        symbol = tokenSymbol;                               
    }

    
    function _transfer(address _from, address _to, uint _value) internal {
        
        require(_to != 0x0);
        
        require(balanceOf[_from] >= _value);
        
        require(balanceOf[_to].add(_value) > balanceOf[_to]);
        
        uint previousBalances = balanceOf[_from].add(balanceOf[_to]);
        
        balanceOf[_from] = balanceOf[_from].sub(_value);
        
        balanceOf[_to] = balanceOf[_to].add(_value);
        emit Transfer(_from, _to, _value);
        
        assert(balanceOf[_from] + balanceOf[_to] == previousBalances);
    }

    
    function transfer(address _to, uint256 _value) public returns (bool success) {
        _transfer(msg.sender, _to, _value);
        return true;
    }

    
    function transferFrom(address _from, address _to, uint256 _value) public returns (bool success) {
        require(_value <= allowance[_from][msg.sender]);     
        allowance[_from][msg.sender] = allowance[_from][msg.sender].sub(_value);
        _transfer(_from, _to, _value);
        return true;
    }

    
    function approve(address _spender, uint256 _value) public
        returns (bool success) {
        allowance[msg.sender][_spender] = _value;
        emit Approval(msg.sender, _spender, _value);
        return true;
    }

    
    function approveAndCall(address _spender, uint256 _value, bytes _extraData)
        public
        returns (bool success) {
        tokenRecipient spender = tokenRecipient(_spender);
        if (approve(_spender, _value)) {
            spender.receiveApproval(msg.sender, _value, this, _extraData);
            return true;
        }
    }

    
    function burn(uint256 _value) public returns (bool success) {
        require(balanceOf[msg.sender] >= _value);   
        balanceOf[msg.sender] = balanceOf[msg.sender].sub(_value);            
        totalSupply = totalSupply.sub(_value);                      
        emit Burn(msg.sender, _value);
        return true;
    }

    
    function burnFrom(address _from, uint256 _value) public returns (bool success) {
        require(balanceOf[_from] >= _value);                
        require(_value <= allowance[_from][msg.sender]);    
        balanceOf[_from] = balanceOf[_from].sub(_value);                         
        allowance[_from][msg.sender] = allowance[_from][msg.sender].sub(_value);             
        totalSupply = totalSupply.sub(_value);                              
        emit Burn(_from, _value);
        return true;
    }
}