Question: how many books in the hitchhiker's guide to the galaxy
[{'answer': 'five', 'provenance': [{'wikipedia_id': '478921', 'title': "The Hitchhiker's Guide to the Galaxy (novel)", 'start_paragraph_id': 5, 'start_character': 18, 'end_paragraph_id': 5, 'end_character': 22, 'bleu_score': 1.0, 'section': 'Section::::Plot summary.\n'}]}, {'provenance': [{'wikipedia_id': '478921', 'title': "The Hitchhiker's Guide to the Galaxy (novel)", 'start_paragraph_id': 1, 'start_character': 0, 'end_paragraph_id': 1, 'end_character': 356, 'bleu_score': 0.821957166363241, 'meta': {'yes_no_answer': 'NONE', 'annotation_id': 7910603197604800893}, 'section': 'Section::::Abstract.'}]}]