import java.util.concurrent.locks.ReentrantLock;

public class Main {
    
    public static void main(String[] args) {
        TellerMonitor monitor = new TellerMonitor();
        Runnable teller = new Teller(monitor);
        Thread teller_traa1 = new Thread(teller);
        Thread teller_traa2 = new Thread(teller);
        teller_traa1.start();
        teller_traa2.start();

    }
}


class Teller implements Runnable {

    private final int MAX_ITERASJONER = 100000;
    private TellerMonitor monitor;

    Teller(TellerMonitor m) {
        monitor = m;
    }

    @Override
    public void run() {
        System.out.println("Startet teller. tallIBoks = " + monitor.hentTallIBoks());
        for (int i = 0; i < MAX_ITERASJONER; i++) {
            monitor.okTall();
        }
        System.out.println("Teller sluttet. tallIBoks = " + monitor.hentTallIBoks());
    }
}

class TellerMonitor {
    private int tallIBoks = 0;
    private ReentrantLock lock = new ReentrantLock();

    void okTall() {
        int tallHentetUt;
        lock.lock();
        try {
            tallHentetUt = tallIBoks;
            tallIBoks = tallHentetUt + 1;
        }
        finally {
            lock.unlock();
        }
    }

    int hentTallIBoks() {
        return tallIBoks;
    }
}