There are 150 students taking Calculus II, Discrete Mathematics II, and Physics I courses. Of these 111 are taking Calculus II, 51 are taking Discrete Mathematics II and 63 are taking Physics I. There are forty one taking Discrete Mathematics II and Calculus II, thirty two students taking Calculus II and Physics I, and 11 students taking Physics I and Discrete Mathematics II. How many of such students are taking exactly two of the three courses?