using System;

public class A

{

    public A()

    {

        Console.WriteLine("iam in a's default constructor");

    }

    public A(int i)

    {

        Console.WriteLine("iam in a's parametrized constructor");

    }

}

public class B :A

{

    public B():base(5)//this is important

    {

        Console.WriteLine("iam in b's default constructor");

    }

    public B(int i):base()//this is important

    {

        Console.WriteLine("iam in b's parametrized constructor");

    }

}

public class Program

{

    public static void Main()

    {

        B obj=new B(5);

    }

}