Write a program to Sort a stack

Solution:

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

namespace StackOperation
{
    class Program
    {
        public static void Main()
        {
            var st = new Stack<int>();
            st.Push(1);
            st.Push(2);
            st.Push(5);
            st.Push(3);
            st.Push(4);

            Console.WriteLine("Stack:");
            foreach (var i in st)
                Console.WriteLine(i);

            st = Sort(st);

            Console.WriteLine("Sort Stack");
            foreach (var i in st)
                Console.WriteLine(i);

            Console.ReadLine();
        }

        public static Stack<T> Sort<T>(Stack<T> input) where T : IComparable<T>
        {
            var tmpStack = new Stack<T>();
            while (input.Any())
            {
                var tmp = input.Pop();

                while (tmpStack.Any() && GreaterThen(tmpStack.Peek(), tmp))
                {
                    input.Push(tmpStack.Pop());
                }
                    
                tmpStack.Push(tmp);
            }   
            return tmpStack;
        }

        static bool GreaterThen<T>(T a, T b) where T : IComparable<T>
        {
            return a.CompareTo(b) < 0;
        }
    }




    public class Stack<T> : IEnumerable<T>
    {
        readonly LinkedList<T> _list = new LinkedList<T>();

        public void Push(T value)
        {
            _list.AddFirst(value);
        }
        public T Pop()
        {
            if (_list.Count == 0)
            {
                throw new InvalidOperationException("The Stack is empty");
            }
            var value = _list.First.Value;
            _list.RemoveFirst();
            return value;
        }

        public T Peek()
        {
            if (_list.Count == 0)
            {
                throw new InvalidOperationException("The Stack is empty");
            }
            return _list.First.Value;
        }

        public int Count()
        {
            return _list.Count;
        }

        public IEnumerator<T> GetEnumerator()
        {
            return _list.GetEnumerator();
        }

        IEnumerator IEnumerable.GetEnumerator()
        {
            return _list.GetEnumerator();
        }
    }
}