using System;

​

public class Father 

{

    string fatherString;

​

    public Father()

    {

        Console.WriteLine("Father Constructor.");

    }

​

    public Father(string myString)

    {

        fatherString = myString;

        Console.WriteLine(fatherString);

    }

​

    public virtual void print()

    {

        Console.WriteLine("I'm a Father Class.");

    }

}

​

public class Child : Father

{

    public Child() : base("From Derived")

    {

        Console.WriteLine("Child Constructor.");

    }

​

    public sealed override void print()

    {

        base.print();

        Console.WriteLine("I'm a Child Class.");

    }

}

​

public class Grandson : Child

{

    public Grandson()

    {

        Console.WriteLine("Grandson Constructor.");

    }

    public override void print()

    {

        base.print();

        Console.WriteLine("I'm a Grandson Class.");

    }

    public static void Main()

    {

        Child child = new Child();

        child.print();

        ((Father)child).print();

        Father child_in_father = new Child();

        child_in_father.print();

    }

}