'Mappe1 is I believe the VB code name for, in my terms, Sheet1. It can be used to refer to the sheet as shown below. You would not Dim Mappe1
To refer to it you could use
Dim ws as worksheet
Set ws = Mappe1
or
Set ws = Sheets("Mappe1")
If you qualify Cells with ws, Mappe1 or other, then Anz will return the value relevant to that sheet, rather than the Active Sheet.
Sub Test1()
'This will return Anz for the Active Sheet
Anz = Cells(Rows.Count, 1).End(xlUp).Row
MsgBox Anz
End Sub
Sub Test2()
'Mappe1 is I believe the VB code name for, in my terms, Sheet1
Anz = Mappe1.UsedRange.Rows.Count
MsgBox Anz
'or
Anz = Sheets("Mappe1").UsedRange.Rows.Count
MsgBox Anz
End Sub