using System;

using System.Collections;

using System.Collections.Generic;

using System.Linq;

​

public class Program

{

    public static void Main()

    {

        Console.WriteLine("Hello World");

        List<string> test = new List<string>();

        test.Add("hello");

        test.Add("how");

        test.Add("are");

        test.Add("you");

        string concated = String.Join(", ", test);

        Console.WriteLine(concated);

    }

}