using System;

interface IAnimal

{

    void Run();

}

​

abstract class Animal : IAnimal 

{

    public abstract void Run();

}

​

class Human : Animal 

{

    public override void Run() 

    {

        Console.WriteLine("Run slow");

    }

}

​

class Chitah : Animal 

{

    public override void Run() 

    {

        Console.WriteLine("Sprint");

    }

}

​

​

public class Program

{

    public static void Main()

    {

        IAnimal a1 = new Animal();

        IAnimal a2 = new Human();

        Animal a3 = new Chitah();

        a1.Run();

        a2.Run();

        a3.Run();

    }

}

​

​