Count number of cells with different entries

Hi
my proble is simple, but i am new to vba programming so be patient please.

I have a table with numbers in different rows (kind of stupid remark, since its excel!). The numbers in the rows stand for a product line. As there are several different products in one product line the same number might come up more than once in one row.

I would now like to count the number of product lines in a coulumn, hence the number of different entries in a column. For example in coulmn J the entries might be: 10 10 10 12 12 12 12 17. I want the makros to display "There are 3 different product lines".

I tried this

Sub Test()

Dim i As Integer
Dim Anzahl As Integer
Dim Zahl As Integer

Zahl = 369490
Anzahl = 1
i = 2
While Not IsEmpty(Cells(10, i))
If Cells(10, i) = Zahl Then
i = i + 1
Else
Zahl = Zahl + 1
Anzahl = Anzahl + 1
End If
Wend
MsgBox "Es gib " & Anzahl & " verschiedene Sendungen!"
End Sub

but it it says "Error 6: Overflow"

Any suggestions?

Thanks!

Ok I kind of found what caused the overflow: The Intger format cant handle the numbers I needed "396054" to "500000" so I changed the format for "Anzahl" and "Zahl" to Long.

Now everytime I start the function my laptop goes nuts
I somehow created a never ending loop. I still dont know what to do. Does someboda have a idea to solve my prob.

Thank you