C987

Faced with Fang Rui's aggressive attitude, the students below immediately started to discuss with each other.

Fang Rui opened a famous book on the side out of boredom. Fang Rui had heard of this famous book before, it was just that he didn't have the time to read it.

"The task of your class is to think about this question. If there is no satisfactory answer to this question