The problem has changed. What I used to see was the sum of the left and right pages, but now it has become a product. I don't know who raised such a question, and I don't know what the purpose is. Anyway, I still want to say that this situation does not exist! There is no answer to this question! Because, in traditional books, page 1 usually starts from the right, so the left page is even and the right page is odd, which is larger than the left page 1, so pages 25 and 26 are on the front and back of a piece of paper, so it is impossible to be on the left and right sides of an open book! Only 24 and 25 pages, 26 and 27 pages can be left and right!