The discrepancy is no more

The wise advice of librarians notwithstanding, the discrepancy of one has been eliminated by my discovery of another 'hidden' item. It's a demonstration that persistence sometimes pays off. There are now 2457 books on the shelves, to match the 2457 titles in the catalogue. Of course, there could be a different kind of discrepancy: maybe there's something on the shelves that's not in the catalogue and vice versa. Oh no...