One of my most cherished possessions is the complete set of the very rare and unknown "Caring For Pests " books (volumes 1 though 5). Each book is 62 millimetres thick, which includes the front and back covers, which are 4 millimetres thick each.

One evening, I sat down and opened one of the books and there was a hole in it! How could this be? It turned out a Worm had eaten through the books, starting on the first page of Volume 1 and eating all the way to the last page of Volume 5.

If the Worm had eaten through the books in the most direct route possible, how many millimetres did the Worm travel?