Factorial of a number using Recursion

Module FactorialRecFunc
    Sub Main()
        Dim n, fact As Integer
        Console.Write("Enter Number : ")
        n = CInt(Console.ReadLine())
        If n < 0 Then
            Console.WriteLine("Factorial of negative number is NOT possible.")
        ElseIf n = 0 Or n = 1 Then
            Console.WriteLine("Factorial of " + n.ToString() + " =1")
        Else
            fact = factorial(n)
            Console.WriteLine("Factorial of " + n.ToString() + " =" + fact.ToString())
        End If
        Console.ReadLine()
    End Sub
    Function factorial(ByVal m As Integer) As Integer
        If m = 0 Then
            Return 1
        Else
            Return m * factorial(m - 1)
        End If
    End Function
End Module