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

namespace TodoApplication
{
    public class LimitedSizeStack<T>
    {
        private int size;
        private LinkedList<T> linkList = new LinkedList<T>();
        public LimitedSizeStack(int size)
        {
            if (size <= 0)
                throw new ArgumentException();
            this.size = size;
        }

        public void Push(T item)
        {
            linkList.AddLast(item);
            if(linkList.Count > size)
                linkList.RemoveFirst();
        }

        public T Pop()
        {
            if (linkList.Count == 0)
                throw new InvalidOperationException();
            var result = linkList.Last.Value;
            linkList.RemoveLast();
            return result;
        }

        public int Count
        {
            get
            {
                return linkList.Count;
            }
        }
    }
}