contract Ownable {

address public owner;

function Ownable() public {
    owner = msg.sender;
}

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

function transferOwnership(address newOwner) public onlyOwner {
    owner = newOwner;
}

}

contract SimpleTokenCoin is Ownable {

string public constant name = "Vozik coin";

string public constant symbol = "VZC";

uint32 public constant decimals = 18;

uint public totalSupply = 1000000;

mapping (address => uint) balances;

mapping (address => mapping(address => uint)) allowed;

function mint(address _to, uint _value) public onlyOwner {
    assert(totalSupply + _value >= totalSupply && balances[_to] + _value >= balances[_to]);
    balances[_to] += _value;
    totalSupply += _value;
}

function balanceOf(address _owner) public constant returns (uint balance) {
    return balances[_owner];
}

function transfer(address _to, uint _value) public returns (bool success) {
    if(balances[msg.sender] >= _value && balances[_to] + _value >= balances[_to]) {
        balances[msg.sender] -= _value; 
        balances[_to] += _value;
        Transfer(msg.sender, _to, _value);
        return true;
    } 
    return false;
}

function transferFrom(address _from, address _to, uint _value) public returns (bool success) {
    if( allowed[_from][msg.sender] >= _value &&
        balances[_from] >= _value 
        && balances[_to] + _value >= balances[_to]) {
        allowed[_from][msg.sender] -= _value;
        balances[_from] -= _value; 
        balances[_to] += _value;
        Transfer(_from, _to, _value);
        return true;
    } 
    return false;
}

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

function allowance(address _owner, address _spender) public constant returns (uint remaining) {
    return allowed[_owner][_spender];
}

event Transfer(address indexed _from, address indexed _to, uint _value);

event Approval(address indexed _owner, address indexed _spender, uint _value);