import java.util.concurrent.*; 
class Problem { 
   // felles data og metoder A 
   static CyclicBarrier b; 

   public static void main(String [] args) { 
      Problem p = new Problem();
      int num = Integer.parseInt(args[0]);
      int threadCount = Integer.parseInt(args[1]);
      if ((threadCount < 2) || (num < 2)) {
         System.out.println("Barrier count: " + num);
         System.out.println("Thread count:  " + threadCount);
         System.exit(0);
      };
      
      b = new CyclicBarrier(num);
      p.utfoer(threadCount); 
      System.out.println(" Main TERMINATED"); 
   } // end main 

   void utfoer (int antT) { 
      Thread [] t = new Thread [antT]; 
      for (int i =0; i< antT; i++) 
         ( t[i] = new Thread(new Arbeider(i))).start(); 
      try { 
        for (int i =0; i< antT; i++) t[i].join(); 
     } catch(Exception e) {} 
   } // end utfoer 

   class Arbeider implements Runnable {
      // lokale data og metoder B
      int ind;

      void sync() {
         try{
            b.await();
         } catch (Exception e) { return;} 
      }

      public Arbeider (int in) {ind = in;};

      public void run() { 
         // kalles naar traaden er startet
         if (ind == 1) try {
            TimeUnit.SECONDS.sleep(10);
         } catch (Exception e) { return;};
         System.out.println("T"+ind+": start");

         if (ind > 1) try {
            System.out.println("T"+ind+": Sleeping a little");
            TimeUnit.SECONDS.sleep(1+ind);
         } catch (Exception e) { return;};

         System.out.println("T"+ind+": trying to pass first time");
         sync();

         System.out.println("T"+ind+": Past first time");

         if (ind > 1) try {
            System.out.println("T"+ind+": Sleeping a little");
            TimeUnit.SECONDS.sleep(1+ind);
         } catch (Exception e) { return;};


         System.out.println("T"+ind+": trying to pass second time");
         sync();

         System.out.println("T"+ind+": Past second time");

         System.out.println("T"+ind+": end");
      } // end run 
   } // end indre klasse Arbeider 
} // end class Problem