2 pages
When I first got my AP last year, they sent 3 pages (2 with the pictures that I submitted and 1 with no picture). When I went to India and came back, the airline kept the copy that had no picture. At the port of entry, the INS people took both copies, stamped them and gave them both back to me.
Now with my AP renewal, I only have 2 documents. The interesting thing to note is that the pictures I sent with the application form are not stuck on these documents. They have actually printed the digital version of my picture. As I mentioned I only got 2 AP documents this time. I spoke with my lawyer and he tells me that the INS is only sending 2 documents now, and your airline should make a copy of one of them and keep for their records. Bottomline is that you can probably make do with just 1 copy of the AP also, as long as the airline and the INS at the port of entry are willing to keep copies.
Please confirm this fact with your lawyer. But it definitely seems that the INS is not sending 3 copies of the AP document.
All the best !