using System;
using System.Collections.Generic;
using System.Linq;
public class Test
{
	public static void Main()
	{
		var lst = new List<string>() {"http://w...content-available-to-author-only...a.com/docs/changelogs/unified/1215/",
			"http://w...content-available-to-author-only...a.com/docs/changelogs/anythingelse/anything/1215/",
			"http://w...content-available-to-author-only...a.com/security/advisory/1047",
			"http://w...content-available-to-author-only...a.com/security/advisory/1048/",
			"http://w...content-available-to-author-only...a.com/doesnt/matter/could/be/anything/1049/"};
		lst.ForEach(m => Console.WriteLine(
			m.Contains("/changelogs/") ? "" : m.Trim('/').Split('/').LastOrDefault()
			));
	}
}

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