using System;

using System.Linq;

public class Program

{

    public static void Main()

    {

        var numbers = Enumerable.Range(0, 10);

​

        while (true)

        {

            Console.Write("Guess a number between 0 and 50: ");

            int guessedNumber;

            if (int.TryParse(Console.ReadLine() ?? string.Empty, out guessedNumber) && numbers.Contains(guessedNumber))

            {

                Console.WriteLine("Found");

                break;

            }

        }

    }

}

​