For college entrance examination papers, which have always been known for their rigorousness, there are problems with their own questions, which are very rare.

Xiao Yang began to wonder if he was wrong, but after repeated careful deliberation, he thought that he was not wrong, and indeed the title was wrong.

Time goes by minute by minute. There are still 20 minutes to go before the exam is over.

Xiao Yang thought about it and decided to write down his ideas on the test paper.

He did not have some problem-solving process, but wrote the problems of the problem itself clearly and clearly.

When Xiao Yang finished his last question,...