/* This class defines a list node for a singly linked list of integers.
   Do not insert any code into this class.
   The automated testing of your program will include this code as
   it is given here.
*/
class ListNode{
   public int data;
   public ListNode next;
   public ListNode(int x, ListNode ptr)
   {
       data= x;
       next= ptr;
   }
}