Main.java

package com.vladislav;

import javax.swing.*;
// Main class in game. He contain main method.
public class Main {

    // Main method run application
    public static void main(String[] args) {
        // Enter hard
        String hard = JOptionPane.showInputDialog(null,
                "Enter hard from 1 to 7:",
                "Game hard");

        int compelexity = hard.charAt(0) - '0';
        if (compelexity >= 1 && compelexity <= 7)
            new Window(compelexity);
        else
            System.out.print("Error on entering game's hard!");
    }
}