Question: The Battle of the Labyrinth is the fourth novel in a pentalogy of adventure and mythological fiction books that have sold more than 45 million copies, and have been sold in how many countries?
{'answer': '35', 'supporting_facts': [['The Battle of the Labyrinth', 0], ['Percy Jackson &amp; the Olympians', 0], ['Percy Jackson &amp; the Olympians', 2]]}