import java.util.concurrent.*
import java.util.concurrent.atomic.*

fun thread(block: fun():Unit ) {
    val thread = object: Thread() {
        override fun run() {
            block()
        }
    }
    thread.start()
}

fun box() : String {
   val ref = AtomicInteger()
   val cdl = CountDownLatch(11)
   for(i in 0..10) {
       thread {
          var current = 0
          do {
              current = ref.synchronized {
                val v = ref.get() + 1
                if(v < 100)
                    ref.set(v+1)
                v
              }
          }
          while(current < 100)
          cdl.countDown()
       }
   }
   cdl.await()
   return if(ref.get() == 100) "OK" else ref.get().toString()
}