Auto Serial number Using VBA

[satahir]

Dear Sir


This code is working perfectly but how can I use this formula for Auto Serial number for specified range for exp A3 to A33 please help

For i = 2 To Cells(Rows.Count,"B").End(xlUp).Row
If Cells(i,"B").Value <> "" Then
Cells(i,"A").Value = i - 1
End If
Next i

Thanks