Faculty attendance on Yom Tov days

Unfortunately, this year there is a week of seminar at the Faculty of Dentistry that falls exactly on Shavuot. Is it permissible to be present there, if we do not write or use the phone, in short, do nothing, just be present there during the day (in terms of that, it is not so much the spirit of the holiday, etc.)
I point out that if we don't come to the seminar, we have a test on a different date, and if we don't do well on the test (a not-so-small chance, but not that great) we stay in the same class for another year.