using System;

public class Program

{

    public static void Main()

    {

         string firstName = "Ai";

         string message = "Good morning";

​

         Console.WriteLine(message + " " + firstName);

         Console.WriteLine($"{message} {firstName}");

​

         string URL = $@"c:¥dir¥{firstName}¥data.txt";

         Console.WriteLine(URL);

    }

}