How to count number of used rows in Excel without opening it?

The below code will demonstrate how to count number of used rows in Excel without opening it - using vbscipt in QTP.

Set objXls=CreateObject("Excel.Application")

Set objWB=objXls.WorkBooks.Open("C:\a.xls")

Set objSheet=objWB.WorkSheets(1)

MsgBox objSheet.UsedRange.Rows.Count

Set objXls=Nothing