Path params without route

Hi,
Wasn't sure how to explain it shortly but essentially i have this file

books.$bookId.pages.$pageNum.tsx

books.$bookId.pages.$pageNum.tsx

and this route should work only as is. So

books.$bookId

books.$bookId

should redirect to 404 page (or to the first page -

books.$bookId.pages.1.tsx

books.$bookId.pages.1.tsx

)

Plus, how do I parse bookId and pageNum as number and where exactly should i parse it?

how can i achieve this? Thank you