using System;

using System.Text;

using System.Security.Cryptography;

public static class Program

{

    public static void Main()

    {

        A a = new A();

        a.PropertyIterator();

    }

    public static void PropertyIterator(this object obj)

    {

        foreach (var prop in obj.GetType().GetProperties())

        {

            if (prop.GetValue(obj).GetType().IsClass)

            {

                Program.PropertyIterator(prop.GetValue(obj));

            }

            Console.WriteLine("I AM HERE");

        }

    }

    public class A

    {

        public B b {get;set;}

    }

    public class B

    {

        public string s {get;set;} = "hello";   

    }

}