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

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

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

  val foo = new Item()
}

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