using System;

public class Program

{

    interface IMessage {

     void DoSomething();    

    }

    class NMSMessage : IMessage {

        public void DoSomething()

        {

            Console.WriteLine("NMS");

        }

    }

    class MockMessage : IMessage {

        public void DoSomething()

        {

            Console.WriteLine("Mock");

        }

    }

    public static void Main()

    {

        IMessage current;

        current = new NMSMessage();

        if(!(current is MockMessage))

        {

            Console.WriteLine("Not Mock");

            current.DoSomething();

        }

        else

        {

            Console.WriteLine("Is Mock");

            current.DoSomething();

        }

        current = new MockMessage();

        if(!(current is NMSMessage))

        {

            Console.WriteLine("Not NMS");

            current.DoSomething();

        }

        else

        {

            Console.WriteLine("Is NMS");

            current.DoSomething();

        }

        Console.WriteLine("Finished");

    }

}