It's not only "Advisory" that will be hit - there will be deep cuts in Audit and Tax as well. Also admin folks will be affected and some will take pay cuts.
Here is what I heard from a partner source:
a) Advisory - about 400
b) Tax - about 200
c) Audit - about 200
There are rumors about compensation reduction, I am not sure how many will be affected there.
Also, there will be about 500 folks laid off in admin and other support functions - EAs have been going through this for a while...