It really depends. During my time 7 years ago, they never said anything about the maximum number of cigarettes we can bring. Neither did they confiscate our cigarettes. However, i was from a WO company. Maybe that's why.
Still, on our first day, my PC singled out all smokers and gave us a long talk about trying to quit or cut down. That was the only thing i remember.
But then, i almost quite smoking during BMT. Why? I had cigarettes, but no time to smoke.
Seriously. I was not a hard core smoker so whenever there was a smoking break, i decided to rest instead. By the time BMT ended, i virtually stopped smoking.
Then i went to unit, and started smoking again. More.