using System;

class baseSample

{

     int a;

     public baseSample(int b) 

     {

         a = b;

         Console.WriteLine(" a ");

     }

     class derivedSample : baseSample

     {

         public derivedSample (int b) : base(b)

         {

             Console.WriteLine(" b ");

         }

     }

     class program

     {

         public static void Main(string[] args)

         {

             derivedSample d =  new derivedSample(20);

         }

     }

}