using System;

​

public class Program

{

    public static void Main()

    {

        string pin = "1234"; 

        string attempt;

​

        while (true)

        {

            Console.WriteLine("Enter PIN: ");

            attempt = Console.ReadLine();

​

            if (attempt != pin)

            {

                Console.WriteLine("Wrong PIN!");

            }

            else

            {

                Console.WriteLine("You entered the right PIN.");

                break;

            }

        }

    }

}