Sum Using Derived Class

Public Class Class1
    Protected a As Integer
    Sub New()
        Console.WriteLine("Inside Class1 Constructor...")
        Console.Write("Enter Number: ")
        a = CInt(Console.ReadLine())
    End Sub
    Sub display()
        Console.WriteLine("a=" + a.ToString())
    End Sub
End Class


Public Class Class2 : Inherits Class1
    Protected b As Integer
    Sub New()
        Console.WriteLine()
        Console.WriteLine("Inside Class2 Constructor...")
        Console.Write("Enter Number: ")
        b = CInt(Console.ReadLine())
    End Sub
    Sub disp()
        Console.WriteLine("b=" + b.ToString())
    End Sub
    Sub add()
        Console.Write("Sum = " + (a + b).ToString())
    End Sub
End Class


Module SumUsingDerivedClass
    Sub Main()
        Dim obj As New Class2
        Console.WriteLine()
        obj.display()
        obj.disp()
        Console.WriteLine()
        obj.add()
        Console.ReadLine()
    End Sub
End Module