using System;

namespace Application
{
    public interface I
    {
        void Go();
    }

    public class A : I
    {
        public void Go()
        {
            Console.WriteLine("A.Go()");
        }
    }

    public class B : A
    {

    }

    public class C : B
    {
        public new void Go()
        {
            Console.WriteLine("C.Go()");
        }
    }

    class MainClass
    {
        public static void Main(string[] args)
        {
            B b1 = new B();
            C c1 = new C();
            B b2 = c1;
            b1.Go();
            c1.Go();
            b2.Go();
            ((I) b2).Go();
        }
    }
}