Private Sub Worksheet_SelectionChange(ByVal Target As Range)
Dim rng As Range

Set rng = Range("A3:A27,B3:B27")
        If Target.Value = Chr(254) Then
            Target.Value = Chr(168)
            Cancel = True
        ElseIf Target.Value = Chr(168) Then
            Target.Value = Chr(254)
            Cancel = True
        End If
End Sub