Sub Absent()
Dim ColonneLettre As String, Colonne As Range
For Each Colonne In Range("B4:BM4")
If InStr(1, "SD", Colonne) > 0 Then
ColonneLettre = Split(Colonne.Address, "$")(1)
Range(ColonneLettre & 6 & ":" & ColonneLettre & 25) = "a"
End If
Next Colonne