using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;

namespace bsuir_1_4
{

    public struct element
    {
        element* Prev;
        int value;
    }

    public interface Stack
    {
        element* Head;
        element* Curr;

        public void Add(int x);
        public void WriteHead();
        public void WriteAll();
        public void Remove(int x);
        public int Count();
    }

    class Program
    {
        static void Main(string[] args)
        {

        }
    }
}