You arrived at school this morning and saw the sports coach opening the sports hall.

The cleaner opens the hall every day except Sundays and Mondays, when the hall either remains closed or is opened by the sports coach. The sports coach is only there for training and for competitive events. The hall is reserved for training in the mornings and events in the afternoons.

The sports coach always arrives fifteen minutes early for both training and events, and schedules them to make sure that they do not occur on the same day.