public class DiningRoom {

  private int count;

  private int waiting;

  public final int MAX = 4;



  DiningRoom() {

    count = 0;

    waiting = 0;

  }



  synchronized void enter() {

    while(count == MAX || waiting > 0) {

      try {

	waiting++;

	wait();

	waiting--;

      } catch(InterruptedException e) {

	System.out.println(e);

      }

    }

    count++;

  }

  

  synchronized void leave() {

    count--;

    notify();

  }



}