Sub Bouton1_Clic()
Application.ScreenUpdating = False
Dim cel As Range
[D2] = LCase(Left([B2], 1) & "." & [A2])
For i = 3 To Range("A65535").End(xlUp).Row
Cells(i, 11) = LCase(Cells(i, 9) & "." & Left(Cells(i, 10), 1))
For Each cel In Range("D2:D" & i - 1)
If Cells(i, 11) = cel Then
Cells(i, 11) = LCase(Left(Cells(i, 9) & "." & Cells(i, 10), Len(cel) + 1))
End If
Next cel
Next i
Application.ScreenUpdating = True
End Sub