Among the 78 doctors on the staff of a hospital, 64 carry malpractice insurance, 36 are surgeons, and 34 of the surgeons carry malpractice insurance. If one of these doctors is chosen by lot to represent the hospital staff at an A.M.A convention (that is, each doctor has a probability of 1/78 of being selected), what is the probability that the one chosen is not a surgeon and does not carry malpractice insurance.