class Cell{
   int info;
   Cell *next;
        Cell(int i){ info = i; next = this; }
        Cell(int i,  Cell *n){ info = i; next = n; }
   friend class List;
};

class List{
   Cell *rear;
public:
   void push(int i){ rear->next = new Cell(i,rear->next); }
   int  pop(){
      if (empty()) return 0;
      Cell *front = rear->next;
      rear->next = front->next;
      int i = front->info;
      delete front;
      return i;
   }
   bool empty(){ return rear == rear->next; }
        List() { rear = new Cell(0); }
        ~List() { while (!empty()) pop(); delete rear; }
};

#include <iostream.h>

   List *listall(int n){
      List *l = new List();
      while (n>0) l->push(n--);
      return l;
   }

   void printall(List *l){
      while (!(l->empty())) cout << l->pop() << '\n';
   }

   main(){
      List *l = new List();
      l->push(1);
      l->push(2);
      List *k = l;
      delete k;
}