using System;

using System.Collections.Generic;

public class Program

{

    public static void Main()

    {

        Stack<int> myStack = new Stack<int>();

        myStack.Push(1);

        myStack.Push(2);

        myStack.Push(3);

        myStack.Push(4);

        Console.WriteLine(myStack.Contains(2)); 

        Console.WriteLine(myStack.Contains(10)); 

    }

}