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. 
