Over the weekend my brother wanted to figure out his class schedule for the next semester. He is a veterinary medicine and zootechnology student at UNAM. For this upcoming semester there is a set of classes he has to take and each has 8 or so instructor options. The website where he finds the class times lists about 8 pre-constructed class schedules. So he normally finds one he likes quite a bit, and then manually starts checking if he can change X instructor for Y for a given class.