Modification de Sommeprod

Function Duo(Plage As Range, item1 As String, item2 As String) As Long
Dim i&, j&
Dim tablo()
j = 1
For i = Plage.Rows.Count To 1 Step -1
    If Plage(i)<> "" Then
        ReDim Preserve tablo(1 To j)
        tablo(j) = Plage(i): j = j + 1
    End If
Next i
Dim tablo2
ReDim tablo2(UBound(tablo))
For i = 1 To UBound(tablo)
    On Error Resume Next
    tablo2(i - 1) = tablo(i + 1)
Next i
For i = 1 To UBound(tablo)
    If tablo(i) = item1 And tablo2(i - 1) = item2 Then Duo = Duo + 1
Next i
End Function