import java.util.*
import java.io.*

class World() {
  public val items: ArrayList<Item> = ArrayList<Item>

  class Item() {
    {
      items.add(this)
    }
  }

  val foo = Item()
}

fun box() : String {
  val w = World()
  if (w.items.size() != 1) return "fail"
  return "OK"
}