import java.util.concurrent.Semaphore;

public class TestSemaphore {
	public static void main(String[] args){
		SharedData sd = new SharedData();
		
		NitA na = new NitA(sd);
		na.start();
		
		NitB nb = new NitB(sd);
		nb.start();
	}
}

class SharedData {
	public int x;
	public int y;
	public int z;
	
	public Semaphore xySem = new Semaphore(0);
	public Semaphore zSem  = new Semaphore(0);
}

class NitA extends Thread {

	public NitA(SharedData data){
		sd = data;
	}
	
	protected SharedData sd;
	
	public void run(){
		int i = 0;
		while(true){
			i++;
			sd.x = i;
			sd.y = i*i;
			sd.xySem.release();
			try {
				sd.zSem.acquire();
			} catch (InterruptedException e) {}
			
			System.out.println( sd.x + " + " + sd.y + " = " + sd.z);
			
			if (i == 10)
				System.exit(0);
		}	
	}
}

class NitB extends Thread{
	public NitB(SharedData data){
		sd = data;
	}
	
	protected SharedData sd;
	
	public void run(){
		while(true){
			try {
				sd.xySem.acquire();
			} catch (InterruptedException e) {}
			
			sd.z = sd.x + sd.y;
			
			sd.zSem.release();
		}
	}
}