using System;

public class Program

{

    public static void Main()

    {

        var str = "abcd@1234";

        var str2 = "abcd1234";

        var ssplit = str.Split("@");

        var ssplit2 = str2.Split("@");

        Console.WriteLine("1. First:{0}\n1. Second:{1}", ssplit[0], ssplit[1]);

        if (ssplit2.Length > 1)

        {

            Console.WriteLine("2. First:{0}\n2. Second:{1}", ssplit2[0], ssplit2[1]);

        }

        else

        {

            Console.WriteLine("2. Only:{0}", ssplit2[0]);

        }

    }

}