using System;

​

// abstract class 'GeeksForGeeks' 

public abstract class GeeksForGeeks { 

    // abstract method 'gfg()' 

    public abstract void gfg(); 

} 

// class 'GeeksForGeeks' inherit 

// in child class 'Geek1' 

public class Geek1 : GeeksForGeeks 

{ 

    // abstract method 'gfg()'  

    // declare here with  

    // 'override' keyword 

    public override void gfg() 

    { 

        Console.WriteLine("class Geek1"); 

    } 

} 

// class 'GeeksForGeeks' inherit in  

// another child class 'Geek2' 

public class Geek2 : GeeksForGeeks 

{ 

    // same as the previous class 

    public override void gfg() 

    { 

        Console.WriteLine("class Geek2"); 

    } 

} 

// Driver Class 

public class main_method { 

    // Main Method 

    public static void Main() 

    { 

        // 'g' is object of class 

        // 'GeeksForGeeks' class ' 

        // GeeksForGeeks' cannot 

        // be instantiate 

        GeeksForGeeks g; 

        // instantiate class 'Geek1' 

        g = new Geek1(); 

        // call 'gfg()' of class 'Geek1' 

        g.gfg(); 

        // instantiate class 'Geek2'   

        g = new Geek2(); 

        // call 'gfg()' of class 'Geek2' 

        g.gfg(); 

    } 

}