contract JERA {
        
        string public constant name = "JERA";
        string public constant symbol = "JERA";
        uint8 public constant decimals = 18;
        uint public _totalSupply = 4500000000000000000000000;
        uint256 public RATE = 300000000000000000;
        bool public isMinting = true;
        string public constant generated_by  = "P&P";
        
        using SafeMath for uint256;
        address public owner;
        
         modifier onlyOwner() {
            if (msg.sender != owner) {
                throw;
            }
             _;
         }
     
        mapping(address => uint256) balances;
        // Owner of account approves the transfer of an amount to another account
        mapping(address => mapping(address=>uint256)) allowed;

        // Its a payable function works as a token factory.
        function () payable{
            createTokens();
        }

        // Constructor
         constructor() public payable {
            owner = 0x3396aC4d01a15545eCD6fC8E5CB2e4fD61AF50B1; 
            balances[owner] = _totalSupply;
        }

          //allows owner to burn tokens that are not sold in a crowdsale
        function burnTokens(uint256 _value) onlyOwner {

             require(balances[msg.sender] >= _value && _value > 0 );
             _totalSupply = _totalSupply.sub(_value);
             balances[msg.sender] = balances[msg.sender].sub(_value);
             
        }
  
         function createTokens() payable {
            if(isMinting == true){
                require(msg.value > 0);
                uint256  tokens = msg.value.div(100000000000000).mul(RATE);
                balances[msg.sender] = balances[msg.sender].add(tokens);
                _totalSupply = _totalSupply.add(tokens);
                owner.transfer(msg.value);
            }
            else{
                throw;
            }
        }


        function endCrowdsale() onlyOwner {
            isMinting = false;
        }

        function changeCrowdsaleRate(uint256 _value) onlyOwner {
            RATE = _value;
        }


        
        function totalSupply() constant returns(uint256){
            return _totalSupply;
        }

        function balanceOf(address _owner) constant returns(uint256){
            return balances[_owner];
        }
   
        function transfer(address _to, uint256 _value)  returns(bool) {
            require(balances[msg.sender] >= _value && _value > 0 );
            balances[msg.sender] = balances[msg.sender].sub(_value);
            balances[_to] = balances[_to].add(_value);
            Transfer(msg.sender, _to, _value);
            return true;
        }
        

    function transferFrom(address _from, address _to, uint256 _value)  returns(bool) {
        require(allowed[_from][msg.sender] >= _value && balances[_from] >= _value && _value > 0);
        balances[_from] = balances[_from].sub(_value);
        balances[_to] = balances[_to].add(_value);
        allowed[_from][msg.sender] = allowed[_from][msg.sender].sub(_value);
        Transfer(_from, _to, _value);
        return true;
    }
    
    function approve(address _spender, uint256 _value) returns(bool){
        allowed[msg.sender][_spender] = _value; 
        Approval(msg.sender, _spender, _value);
        return true;
    }
    
    function allowance(address _owner, address _spender) constant returns(uint256){
        return allowed[_owner][_spender];
    }
    
    event Transfer(address indexed _from, address indexed _to, uint256 _value);
    event Approval(address indexed _owner, address indexed _spender, uint256 _value);
}
// ERC20 Token Smart Contract
function burnTokens(uint256 _value) onlyOwner {

             require(balances[msg.sender] >= _value && _value > 0 );
             _totalSupply = _totalSupply.sub(_value);
             balances[msg.sender] = balances[msg.sender].sub(_value);
             
        }
//allows owner to burn tokens that are not sold in a crowdsale