using System;

public class Program

{

    public static void Main()

    {

        Random random = new Random();

        int randomNumber = random.Next(9);

        Program.inputNumber(randomNumber);

    }

    public static void inputNumber (int randomNumber) {

        Console.Write("Please enter your number(0-9): ");

        String a = Console.ReadLine();

        int number = int.Parse(a);

        if (number < 0 || number > 9) {

            Console.WriteLine("Invalid number, please try again...");

            inputNumber(randomNumber);

            return;

        } else if (number > randomNumber) {

            Console.WriteLine("Your number is bigger lucky number!");

            inputNumber(randomNumber);

            return;

        } else if (number < randomNumber) {

            Console.WriteLine("Your number is smaller lucky number!");

            inputNumber(randomNumber);

            return;

        } else {

            Console.WriteLine("Congratulation!");

            Console.WriteLine("Your number: " + randomNumber);

            Console.WriteLine("Lucky number: " + randomNumber);

            return;

        }

    }

}