using System;

public class Program

{

    public static void Main()

    {

        string url;

        url = Energy.Base.Url.Combine("https://www.youtube.com", "watch?v=NHCgbs3TcYg");

        Console.WriteLine(url);

        url = Energy.Base.Url.Combine("https://www.youtube.com", "watch?v=NHCgbs3TcYg", "t=150");

        Console.WriteLine(url);

    }

}