using System;

using System.Text.RegularExpressions;

​

public class Program

{

    //private static readonly Regex numberR = new Regex(@"^\d+$");

    private static readonly Regex numberR = new Regex(@"^[*]$");

    public static void Main()

    {

        string s = "sam*";

​

        if (numberR.IsMatch(s))

        {

            Console.WriteLine("Given string is numeric");

        }

        else

        {

            Console.WriteLine("Given string is non-numeric");

        }

    }

}