public class Semaphore{
	private int s = 0;
	
	public Semaphore(int i){
		initS(i);
	}
	
	public synchronized void initS(int i){
		s = i;
	}
	public synchronized void waitS(){
		while (s == 0) {
  		  try {
			wait();
		  } catch (InterruptedException e) { }
		}
		s = s - 1;
		notifyAll();
	}

	public synchronized void signalS(){
		s = s + 1;
		if ( s == 1) notifyAll();
	}
}