If Not Intersect(Target, Settings.Range("C4")) Is Nothing Then

Private Sub Worksheet_Change(ByVal Target As Range)
Dim a, d As Integer
d = Settings.Range("C4").Value
    If Not Intersect(Target, Settings.Range("C4")) Is Nothing Then
        Application.EnableEvents = False
            Application.ActiveSheet.Rows("5:36").Hidden = False
            a = d + 4
            Rows(a & ":35").Hidden = True
            Range("B36") = d
            Application.ActiveSheet.Rows("41:70").Hidden = False
            a = d + 40
            Rows(a & ":71").Hidden = True
            Range("B72") = d
    End If
        Application.EnableEvents = True
End Sub