At half-past five in the afternoon, during the Math Olympiad training class, Albert had just finished explaining the last problem. So, he closed the textbook and said, "We've covered all topics. Does anyone have any questions? If not, you can all head back early today. Review what you need to, get a good night's rest, and don't let it affect your performance tomorrow. And one last thing, don't be late, and don't forget to bring your admission tickets."

After giving some additional instructions,