Program to check given element exists in stack or not in C#

using System;
using System.Collections;

namespace ConsoleApplication1
{
    
    class Program
    {
        static void Main()
        {
            Stack S = new Stack(5);

            S.Push(10);
            S.Push(20);
            S.Push(30);
            S.Push(40);

            if (S.Contains(30))
                Console.WriteLine("Item found in stack");
            else
                Console.WriteLine("Item did not find in stack");
            
        }
    }
}

Output

Item found in stack

In this program, we are pushing 4 elements (10,20,30,40) in stack, and then we are checking item 30 is exist in stack or not using Contains method of Stack class?

Note: In above program, to use 'Stack' class, we need to include System.Collection namespace.