Sub Zaehlen()
Dim lngLz As Long
Dim lngCnt As Long
Set wsakt = ThisWorkbook.Sheets(1)
lngLz = wsakt.Cells(Rows.Count, 1).End(xlUp).Row
wsakt.Columns(2).ClearContents
For a = 2 To lngLz
lngCnt = 1
For b = a To lngLz
If wsakt.Cells(b, 1).Value = wsakt.Cells(a, 1).Value And _
wsakt.Cells(b, 2).Value = "" Then
wsakt.Cells(b, 2).Value = wsakt.Cells(b, 1).Value & "." & lngCnt
lngCnt = lngCnt + 1
End If
Next b
Next a
End Sub