using System;
using System.Linq;
using System.IO;

public class Test
{
	public static void Main()
	{
	    String[]uris = new[]{ "http://s...content-available-to-author-only...1.org/info.php","http://s...content-available-to-author-only...2.com/info/index.php","http://s...content-available-to-author-only...3.edu/", "http://s...content-available-to-author-only...3.edu/", "no uri", "" };
	    var result = uris.Where(u => Uri.IsWellFormedUriString(u, UriKind.Absolute))
            .Select(u => { 
                var p = new Uri(u).ToString();
                return p.Substring(0, p.LastIndexOf('/') +1); 
            })
            .Distinct()
            .ToArray();

            Console.Write(String.Join(Environment.NewLine,result));
	}
}