Question

An anonymous survey of college students was taken to determine behaviors regarding alcohol, cigarettes, and illegal drugs. The results were as follows: 827 drank alcohol regularly, 645 smoked cigarettes, 183 used illegal drugs, 398 drank alcohol regularly and smoked cigarettes, 112 drank alcohol regularly and used illegal drugs, 108 smoked cigarettes and used illegal drugs, 88 engaged in all three behaviors, and 175 engaged in none of these behaviors.

How many students engaged in at least one of these behaviors?