using System;

using System.Text.RegularExpressions;

public class Program

{

    public static void Main()

    {

        string numberPattern = @"^\b[0-9]{1,}\b$";

        string numberTest = "";

        while (numberTest != "exit")

        {

            Console.WriteLine("Give number to test:");

            numberTest = Console.ReadLine();

            if (numberTest == "exit")

                break;

            Console.WriteLine(Regex.IsMatch(numberTest, numberPattern));

        }

    }

}