Private Sub Worksheet_Change(ByVal Target As Range)
If Intersect(Target, [C1]) Is Nothing Then Exit Sub
Application.ScreenUpdating = False
Rows.Hidden = False
If IsEmpty([C1]) Then Exit Sub
On Error Resume Next
With [IV3].Resize(Application.Count([B:B]))
.FormulaR1C1 = "=LN(AND(RC3<>R1C3,RC7<>R1C3))"
.SpecialCells(xlCellTypeFormulas, 1).EntireRow.Hidden = True
.ClearContents
End With
End Sub