using System;

using System.Collections.Generic;

​

public class Program

{

    public static void Main()

    {

        Stack<string> planets = new Stack<string>();

        // Add items for testing

        planets.Push("Mercury");

        planets.Push("Venus");

        planets.Push("Earth");

​

        // Contains() to check and return Boolean value if item exists or not. 

        Console.WriteLine(planets.Contains("Venus")); // Return True

    }

}