Public Function total_durée(marque As Range, mois As Range)
With Sheets("DMP-")
For Each c In .Range("K2:T" & .Range("J65000").End(xlUp).Row)
If c = marque And .Cells(c.Row, 23) = mois Then _
tot = tot + .Cells(c.Row, 3)
Next c
End With
total_durée = tot
End Function