[Phonella]

I am new to Calibre and so far have found it exceedingly useful. But one thing puzzles me and leaves me a little disconcerted:

Why does the folder which is created when I add a book have a number sequence in its name?

The number's presence distracts me and I wish that it was not added to the folder name. Is it possible to turn this numbering affair off? Or is it necessary for some reason?

Thanks for your reply.