Iam teaching a class that has n teaching assistants, each of whom hold office hours outside, at javacity. the ith ta holds office hours starting at time si and ending at time ei . each ta holds exactly one office hour (which may last any amount of time, not necessarily one hour, and different tas may have different interval lengths, which may overlap with one another). attendance has been low because students, being ics majors, are afraid of the sun, so the department announces that all tas who do not have a student visit them this week will be fired . because all of our teaching assistants are awesome 2 , we want to ensure that none get fired. however, due to student fears of the sun, we want to minimize the total number of visits made to tas.