public static void Main()
 {
     LinkedList<int> list = new LinkedList<int>();
         list.AddAtTheEnd(5);
         list.AddAtTheEnd(10);
         list.AddAtTheEnd(20);
         list.AddAtTheEnd(30);
         list.AddAtBeggining(1000);
         list.RemoveFirst();
         list.RemoveLast();
 }