contract TokenERC20 is owned{
    using SafeMath for uint256;
    // Public variables of the token
    string public name;
    string public symbol;
    uint8 public decimals = 18;
    // 18 decimals is the strongly suggested default, avoid changing it
    uint256 public totalSupply;
    bool public released = true;
    // This creates an array with all balances
    mapping (address => uint256) public balanceOf;
    mapping (address => mapping (address => uint256)) public allowance;
    // This generates a public event on the blockchain that will notify clients
    event Transfer(address indexed from, address indexed to, uint256 value);
    // This generates a public event on the blockchain that will notify clients
    event Approval(address indexed _owner, address indexed _spender, uint256 _value);
    // This notifies clients about the amount burnt
    event Burn(address indexed from, uint256 value);
    constructor(
        uint256 initialSupply,
        string tokenName,
        string tokenSymbol
    ) public {
        totalSupply = initialSupply * 10 ** uint256(decimals); // Update total supply with the decimal amount
        balanceOf[msg.sender] = totalSupply; // Give the creator all initial tokens
        name = tokenName; // Set the name for display purposes
        symbol = tokenSymbol; // Set the symbol for display purposes
    }
    function release() public onlyOwner{
        require (owner == msg.sender);
        released = !released;
    }
    modifier onlyReleased() {
        require(released);
        _;
    }
    function _transfer(address _from, address _to, uint _value) internal onlyReleased {
        // Prevent transfer to 0x0 address. Use burn() instead
        require(_to != 0x0);
        // Check if the sender has enough
        require(balanceOf[_from] >= _value);
        // Check for overflows
        require(balanceOf[_to] + _value > balanceOf[_to]);
        // Save this for an assertion in the future
        uint previousBalances = balanceOf[_from].add(balanceOf[_to]);
        // Subtract from the sender
        balanceOf[_from] = balanceOf[_from].sub(_value);
        // Add the same to the recipient
        balanceOf[_to] = balanceOf[_to].add(_value);
        emit Transfer(_from, _to, _value);
        // Asserts are used to use static analysis to find bugs in your code. They should never fail
        assert(balanceOf[_from].add(balanceOf[_to]) == previousBalances);
    }
    /**
        * Transfer tokens
    *
        * Send `_value` tokens to `_to` from your account
    *
        * @param _to The address of the recipient
    * @param _value the amount to send
    */
    function transfer(address _to, uint256 _value) public onlyReleased returns (bool success) {
        _transfer(msg.sender, _to, _value);
        return true;
    }
    /**
        * Transfer tokens from other address
    *
        * Send `_value` tokens to `_to` in behalf of `_from`
    *
        * @param _from The address of the sender
    * @param _to The address of the recipient
    * @param _value the amount to send
    */
    function transferFrom(address _from, address _to, uint256 _value) public onlyReleased returns (bool success) {
        require(_value <= allowance[_from][msg.sender]); // Check allowance
        allowance[_from][msg.sender] = allowance[_from][msg.sender].sub(_value);
        _transfer(_from, _to, _value);
        return true;
    }
    /**
        * Set allowance for other address
    *
        * Allows `_spender` to spend no more than `_value` tokens in your behalf
    *
        * @param _spender The address authorized to spend
    * @param _value the max amount they can spend
    */
    function approve(address _spender, uint256 _value) public onlyReleased
    returns (bool success) {
        require(_spender != address(0));
        allowance[msg.sender][_spender] = _value;
        emit Approval(msg.sender, _spender, _value);
        return true;
    }
    function approveAndCall(address _spender, uint256 _value, bytes _extraData)
    public onlyReleased
    returns (bool success) {
        tokenRecipient spender = tokenRecipient(_spender);
        if (approve(_spender, _value)) {
            spender.receiveApproval(msg.sender, _value, this, _extraData);
            return true;
        }
    }
    /**
        * Destroy tokens
    *
        * Remove `_value` tokens from the system irreversibly
    *
        * @param _value the amount of money to burn
    */
    function burn(uint256 _value) public onlyReleased returns (bool success) {
        require(balanceOf[msg.sender] >= _value); // Check if the sender has enough
        balanceOf[msg.sender] = balanceOf[msg.sender].sub(_value); // Subtract from the sender
        totalSupply = totalSupply.sub(_value); // Updates totalSupply
        emit Burn(msg.sender, _value);
        return true;
    }
    /**
        * Destroy tokens from other account
    *
        * Remove `_value` tokens from the system irreversibly on behalf of `_from`.
        *
        * @param _from the address of the sender
    * @param _value the amount of money to burn
    */
    function burnFrom(address _from, uint256 _value) public onlyReleased returns (bool success) {
        require(balanceOf[_from] >= _value); // Check if the targeted balance is enough
        require(_value <= allowance[_from][msg.sender]); // Check allowance
        balanceOf[_from] = balanceOf[_from].sub(_value); // Subtract from the targeted balance
        allowance[_from][msg.sender] = allowance[_from][msg.sender].sub(_value); // Subtract from the sender's allowance
        totalSupply = totalSupply.sub(_value); // Update totalSupply
        emit Burn(_from, _value);
        return true;
    }
}
function approve(address _spender, uint256 _value) public onlyReleased
    returns (bool success) {
        require(_spender != address(0));
        allowance[msg.sender][_spender] = _value;
        emit Approval(msg.sender, _spender, _value);
        return true;
    }
/**
 * Set allowance for other address
 *
 * Allows `_spender` to spend no more than `_value` tokens in your behalf
 *
 * @param _spender The address authorized to spend
 * @param _value the max amount they can spend
 */