program TurnstileMain{
    Turnstile turnstile1;
    Turnstile turnstile2;
    Turnstile turnstile3;
    Counter c;
    cobegin{
        c = new Counter();
        turnstile1 = new Turnstile(c);
        turnstile2 = new Turnstile(c);	
        turnstile3 = new Turnstile(c);
    }
    System.out.printf("counter value: %d\n", c.getValue());

}