Private Sub Worksheet_Change(ByVal Target As Range)
Dim a As Range, b As Range, c As Range
Set a = Intersect([RegionToFill], Target)
If Not a Is Nothing Then
  Application.EnableEvents = False
  Range("A2") =  0 
  For Each c In [RegionToFill].Columns
    Set a = Nothing: Set b = Nothing
    On Error Resume Next
    Set a = c.SpecialCells(xlCellTypeConstants)
    Set b = c.SpecialCells(xlCellTypeFormulas)
    If Not (a Is Nothing And b Is Nothing) Then
      Range("A2") = Range("A2") +  1 
    End If
    On Error GoTo  0 
  Next c
  Application.EnableEvents = True
End If
End Sub