A sophomore class of 36 mathematics majors was surveyed about some of their health habits. Twelve students are vegetarian, sixteen students drink eight glasses of water a day, and twenty-two students exercise at least twice a week. Five students practice all three habits. Seven students are vegetarians and drink eight glasses of water a day; nine students are vegetarian and exercise at least twice a week; and eleven students drink eight glasses of water a day and exercise at least twice a week. What is the probability that a sophomore mathematics major selected at random practices exactly one of the three health habits