Imports System

Imports Microsoft.VisualBasic

Public Module Module1

    Public Sub Main()

        Dim cnt as integer

        Dim bio(19) as double

        Dim eng(19) as double

        Dim a as Boolean

        Dim sumB as double

        Dim sumE as double

        Dim avg as double

        For cnt = 0 to 19 

        Console.WriteLine("Enter Biology marks out of 20")

        bio(cnt) = Console.ReadLine()

        a = IsNumeric (bio(cnt))

        If a = True 

            If bio(cnt) >=0 & bio(cnt) <= 0 

                sumB = sumB + bio(cnt)

            Else if

                    Repeat 

    End Sub

End Module