Function ColD$(colRef As Range, Optional Décalage%)
Dim C%, M%, A$, Ref As Range
On Error Resume Next
For Each Ref In colRef.Cells
C = Columns(Ref.Value).Column: If M < C Then M = C
Next Ref
A = Columns(M - Décalage * (M > 0)).Address(, 0)
ColD = Left$(A, Len(A) \ 2)
End Function