Private Sub Worksheet_Change(ByVal Target As Range)
If Not Application.Intersect(Target, Range("K:K, O:O, P:P")) Is Nothing Then
If IsNumeric(Left(Target, 1)) And Not IsNumeric(Left(Target, 2)) _
And Left(Target, 1) <> 0 And Len(Target) > 1 Then _
MsgBox "ok "
End If
End Sub