Incrémenter un nombre dans une feuille Excel

Private Sub Workbook_BeforePrint(Cancel As Boolean)
    Dim nb As Long, i As Long, c As Long, sh As Worksheet
    Dim listeCell(), nbCell As Long, part1 As String, part2 As Long
    listeCell = Array("C1", "E1", "G1")
    nbCell = UBound(listeCell) + 1
    Set sh = ActiveSheet
    If sh.Name <> "Feuil1" Then Exit Sub
    Cancel = True
    On Error GoTo suite
    nb = CInt(InputBox("Nombre d'exemplaires à imprimer ", "Impression"))
    On Error GoTo 0
    Application.EnableEvents = False
    For i = 1 To nb
        ' imprimer feuille
        sh.PrintOut Copies:=1, Collate:=True
        ' n° suivants
        For c = 0 To nbCell - 1
            part1 = Left(sh.Range(listeCell(c)), 1)
            part2 = CInt(Mid(sh.Range(listeCell(c)), 2))
            sh.Range(listeCell(c)).Value = part1 & part2 + nbCell
        Next c
    Next i
suite:
    Application.EnableEvents = True
End Sub