import java.util.concurrent.locks.ReentrantLock;

class Main {

    public static void main(String[] args) {
        TellerMonitor monitor = new TellerMonitor();
        Runnable task = new MinOppgave(monitor);
        Thread peter = new Thread(task);
        Thread daniel = new Thread(task);

        peter.start();
        daniel.start();
        
    }
}


class MinOppgave implements Runnable {
    private final int MAX_ITERATIONS = 100000;
    private TellerMonitor monitor;

    MinOppgave(TellerMonitor m) {
        monitor = m;
    }

    @Override
    public void run() {
        System.out.println("Starter telling.  TellerMonitor.teller = " + monitor.hentTeller());
        for (int i = 0; i < MAX_ITERATIONS; i++) {
            
            monitor.okteller();
        }
        System.out.println("Ferdig med telling. TellerMonitor.teller = " + monitor.hentTeller());
    }
}

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

    public void okteller() {
        lock.lock();
        try {
            deltTeller += 1;
        }
        finally {
            lock.unlock();
        }
    }

    public int hentTeller() {
        return deltTeller;
    }
}