using System;

public class Program

{

    public static void Main()

    {

        Console.WriteLine(nameof(Class3.C2Cls2.C1Cls1));

        Console.WriteLine("Hello World".Contains("ELLO", StringComparison.CurrentCultureIgnoreCase));

        string nullVal = null;

        Console.WriteLine((nullVal + "+"));

    }

    public class Class1

    {

        public string C1Attr1 { get; set; } 

    }

    public class Class2

    {

        public string C2Attr1 { get; set; } 

        public Class1 C1Cls1 { get; set; }  

    }

    public class Class3

    {

        public string C3Attr1 { get; set; } 

        public Class2 C2Cls2 { get; set; }  

    }

}