Page Layout ⇒ How to add frame numbers of beamer presentation to PDF?

[fllniks]

Recently, I saw a pdf file of the beamer presentation where the Adobe Acrobat was showing frame numbers. For example in the Acrobat toolbar, it showed 15 (5 of 20).
That means there were 20 frames and I was seeing 5th frame.

I would like to add a command in my beamer presentation so that it shows frame numbers in the pdf file.
I know how to show frame numbers in the pdf output. How does one show it in Acrobat toolbar?