How to find out Total No of Pages of a Report Output in sap abap

I want to find out total no of pages of a report output. This no I have to print in TOP-OF-PAGE event.

Check this below code. You will get the clear idea.

REPORT YJAM_WA no standard page heading line-count 60(5).

data: v_totpage type i.
data: v_temp(3) type c.
Start-of-selection.
do 100 times.
write:/ sy-index.
enddo.

end-of-selection.
v_temp = v_totpage.
do v_totpage times.
read line 1 of page sy-index.
replace '@@@' in sy-lisel with v_temp.
modify line 1 of page sy-index.
enddo.

top-of-page.
write:/60 'page', sy-pagno, '/','@@@'.
v_totpage = sy-pagno.

Here is a sample:

* zlines number of lines in the table
* sy-srows number of lines in screen
* sy-cpage current page
* zpages total number of pages type i
* temp temporary number type f
describe table itab lines zlines.
temp = zlines / sy-srows.
zpages = trunc( temp ).
temp = frac( temp ).
if temp > 0.
zpages = zpages + 1.
endif.
* zpages is the number of pages
write: /'Page ',sy-cpage, ' of ', zpages.