// Vulnerability label: clean
/*
    The United Crypto System is an unique Blockchain-based system that combines three key elements:
UCS Gambling (Cryptocurrency Casino)
UCS Dapps (Game Applications)
UCS Bet (Sports Betting)
    The platform will provide access to the three most popular destinations in the niche, using a single cryptocurrency and wallet.
    The United Crypto System is an unique system, the first and only in the world, which will bring dividends to each investor (100% of net profit is subject to distribution throughout the project's lifetime) and an additional percentage (from 3% to 150%) for each month ownership investment token. 
    The United Crypto System is an issuer of 2 (Two) types of tokens: 
  UBS Token - Investment Security token, which will allow you to receive a guaranteed income over the long period of investor investment.
  UCS Token - Utility token to be used on the platform as a means of payment. 
  
    The sooner you join our United Crypto System Token Sale, the more you will earn. 
For example, if you invest in pre-ICO or ICO, then in September after IEO you will be able to get more than 10000% of profit.
    IEO (Initial Exchange Offering) of the United Crypto System tokens is scheduled for August-September 2019. 

Our website https://casinosinvest.com 
Our telegram channel https://t.me//Unitedsystem 
Our telegram chat https://t.me//Casinosystem

*/

pragma solidity ^0.5.0;
interface IERC20 {
    function transfer(address to, uint256 value) external returns (bool);

    function approve(address spender, uint256 value) external returns (bool);

    function transferFrom(address from, address to, uint256 value) external returns (bool);

    function totalSupply() external view returns (uint256);

    function balanceOf(address who) external view returns (uint256);

    function allowance(address owner, address spender) external view returns (uint256);

    event Transfer(address indexed from, address indexed to, uint256 value);

    event Approval(address indexed owner, address indexed spender, uint256 value);
}

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;
    }
}

contract ERC20 is IERC20 {
    using SafeMath for uint256;

    mapping (address => uint256) private _balances;

    mapping (address => mapping (address => uint256)) private _allowed;

    uint256 private _totalSupply;

    function totalSupply() public view returns (uint256) {
        return _totalSupply;
    }

    function balanceOf(address owner) public view returns (uint256) {
        return _balances[owner];
    }

    function allowance(address owner, address spender) public view returns (uint256) {
        return _allowed[owner][spender];
    }

    function transfer(address to, uint256 value) public returns (bool) {
        require(block.timestamp > 1564617600, "Tokens transfers are prohibited until August 1, 2019");

        _transfer(msg.sender, to, value);
        return true;
    }

    function approve(address spender, uint256 value) public returns (bool) {
        require(spender != address(0));

        _allowed[msg.sender][spender] = value;
        emit Approval(msg.sender, spender, value);
        return true;
    }

    function transferFrom(address from, address to, uint256 value) public returns (bool) {
        _allowed[from][msg.sender] = _allowed[from][msg.sender].sub(value);
        _transfer(from, to, value);
        emit Approval(from, msg.sender, _allowed[from][msg.sender]);
        return true;
    }

    function increaseAllowance(address spender, uint256 addedValue) public returns (bool) {
        require(spender != address(0));

        _allowed[msg.sender][spender] = _allowed[msg.sender][spender].add(addedValue);
        emit Approval(msg.sender, spender, _allowed[msg.sender][spender]);
        return true;
    }

    function decreaseAllowance(address spender, uint256 subtractedValue) public returns (bool) {
        require(spender != address(0));

        _allowed[msg.sender][spender] = _allowed[msg.sender][spender].sub(subtractedValue);
        emit Approval(msg.sender, spender, _allowed[msg.sender][spender]);
        return true;
    }

    function _transfer(address from, address to, uint256 value) internal {
        require(to != address(0));

        _balances[from] = _balances[from].sub(value);
        _balances[to] = _balances[to].add(value);
        emit Transfer(from, to, value);
    }

    function _mint(address account, uint256 value) internal {
        require(account != address(0));

        _totalSupply = _totalSupply.add(value);
        _balances[account] = _balances[account].add(value);
        emit Transfer(address(0), account, value);
    }

    function _burn(address account, uint256 value) internal {
        require(account != address(0));

        _totalSupply = _totalSupply.sub(value);
        _balances[account] = _balances[account].sub(value);
        emit Transfer(account, address(0), value);
    }

    function _burnFrom(address account, uint256 value) internal {
        _allowed[account][msg.sender] = _allowed[account][msg.sender].sub(value);
        _burn(account, value);
        emit Approval(account, msg.sender, _allowed[account][msg.sender]);
    }
}

library Roles {
    struct Role {
        mapping (address => bool) bearer;
    }

    function add(Role storage role, address account) internal {
        require(account != address(0));
        require(!has(role, account));

        role.bearer[account] = true;
    }

    function remove(Role storage role, address account) internal {
        require(account != address(0));
        require(has(role, account));

        role.bearer[account] = false;
    }

    function has(Role storage role, address account) internal view returns (bool) {
        require(account != address(0));
        return role.bearer[account];
    }
}

contract MinterRole {
    using Roles for Roles.Role;

    event MinterAdded(address indexed account);
    event MinterRemoved(address indexed account);

    Roles.Role private _minters;

    constructor () internal {
        _addMinter(msg.sender);
    }

    modifier onlyMinter() {
        require(isMinter(msg.sender));
        _;
    }

    function isMinter(address account) public view returns (bool) {
        return _minters.has(account);
    }

    function addMinter(address account) public onlyMinter {
        _addMinter(account);
    }

    function renounceMinter() public {
        _removeMinter(msg.sender);
    }

    function _addMinter(address account) internal {
        _minters.add(account);
        emit MinterAdded(account);
    }

    function _removeMinter(address account) internal {
        _minters.remove(account);
        emit MinterRemoved(account);
    }
}

contract ERC20Mintable is ERC20, MinterRole {
    function mint(address to, uint256 value) public onlyMinter returns (bool) {
        _mint(to, value);
        return true;
    }
}

contract UBS is ERC20Mintable {
  string public constant name = "United Crypto System";
  string public constant symbol = "UBS";
  uint8 public constant decimals = 18;
}