using System;

using System.Text.RegularExpressions;

public class Program

{

    public static void Main()

    {

        var lines = new []

        {

            "09103,09101,",

            "09103,09101",

            "12345,1234567",

            "12345,123456789",

            "12345"

        };

        var re = new Regex(@"^\d{1,5}(,(\d{5}|\d{9}))?,?$");

        foreach (var line in lines)

        {

            Console.WriteLine("{0} = {1}", line, re.IsMatch(line) ? "Valid" : "Invalid");

        }

    }

}