class Counter {
    int x = 0, y = 0;
    public void increment() {
        if (x != y) {
            System.out.println("x = " + x + "; y = " + y);
            x = y = 0;
        }
        x++;
        y++;
    }
}
class Worker implements Runnable {
    private Counter counter;
    public Worker (Counter c) {
        counter = c;
    }
    public void run() {
        for(int i = 0; i < 500000000; i++)
            counter.increment();
    }
}
public class counter {
//    public static final void main (String[] args) {
//        Counter c1 = new Counter();
//        Worker w1 = new Worker(c1);
//        w1.run();
//        Counter c2 = new Counter();
//        Worker w2 = new Worker(c2);
//        w2.run();
//        System.out.println("c1: x = " + c1.x + "; y = " + c1.y);
//        System.out.println("c2: x = " + c2.x + "; y = " + c2.y);
//    }
    public static final void main (String[] args) {
        Counter c1 = new Counter();
        Worker w1 = new Worker(c1);
        Thread t1 = new Thread(w1);
        t1.start();
        Counter c2 = new Counter();
        Worker w2 = new Worker(c1);
        Thread t2 = new Thread(w2);
        t2.start();
        try {
            t1.join();
            t2.join();
        } catch (InterruptedException x) {
        }
        System.out.println("c1: x = " + c1.x + "; y = " + c1.y);
        System.out.println("c2: x = " + c2.x + "; y = " + c2.y);
    }
}