using System;

using System.Collections.Generic;

​

public class Program

{

    public static void Main()

    {

        var str = string.Join(",", "1234", "1");

        var str2 = string.Join(",", "12345", "1");

        Console.WriteLine(str + " " + str2);

        str = string.Join("1234", "1");

        str2 = string.Join("12345", "1");

        Console.WriteLine(str + " " + str2);

    }

}