using System;

using System.Linq;

public class Program

{

    public static void Main()

    {

        var uri = new Uri("https://zignsecfilestorage.blob.core.windows.net/images-test/aaaa/bbbb?sv=2018-11-09&sr=b&sig=MUDoZ8oTmVXW8fHltfaH48nAT2Bfd%2BQS%2FiemGUapSNk%3D&st=2019-07-31T07%3A47%3A56Z&se=2019-09-29T07%3A47%3A56Z&sp=r");

        // We want aaaa/bbbb

        Console.WriteLine(string.Join("", uri.Segments.Reverse().Take(2)));

    }

}