public class QueueOfInts {

   ListOfInts list;

   public QueueOfInts() {
      list = new ListOfInts();
   }

   public boolean isEmpty() { return list.isEmpty(); }

   public void enqueue(int n) {
      list.append(n);
   }
   public int dequeue() {
      if (isEmpty()) throw new Error("Stack underflow");
      list.reset();
      int ans = list.getItem();
      list.delete();
      return ans;
   }
}