at the end of each period, the student chooses the classes they want to take. on each class, the students are listed by their cr(which is ufabc's version of the gpa) and the first ones will attend that class on the next period. however, if the class is from a specific course, the criteria becomes the cp(a number ranging from 0 to 1 that indicates how much of that specific course was completed by that student). all disciplines have an associated "credit", which represents the number of classes per two weeks.