mutex = Semaphore(1)
ES = Semaphore(0)
WS = Semaphore(0)
int EC = 0, WC = 0, rope = 0

Process East
   mutex.wait()
   if (rope==5 or WC>0) {
      EC += 1
      mutex.signal()
      ES.wait()
   }
   rope += 1
   mutex.signal();
   # cross
   mutex.wait();
   rope -= 1
   if (wc > 0 and rope == 0) {
      wc -= 1
      wc.signal();
   }
   else if (EC > 0 and rope < 5) {
      EC -= 1
      ES.signal();
   }
   else 
      mutex.signal();