sclass IntVar {
  int a; // you can access this directly if you use one thread
  
  public synchronized void set(int v) {
    if (v != a) {
      a = v;
      notifyAll();
    }
  }
  
  public synchronized int get() { ret a; }

  synchronized int waitForValue(int x) ctex {
    while (a != x) wait();
    ret a;
  }
  
  toString { ret str(this!); }
}