Function Factorial Learn programming Visual Basic (VB.net)

Imports System
Public Class Exercise114
    Public Shared Function Factorial(ByVal num As Integer) As Integer
        If num = 0 Then
            Return 1
        Else
            Return num * Factorial(num - 1)
        End If
    End Function

    Public Shared Sub Main()
        Console.WriteLine("Enter a number:")
        Dim number As Integer = Convert.ToInt32(Console.ReadLine())
        Console.WriteLine(Factorial(number))
        Console.WriteLine(Factorial(6))
    End Sub
End Class