Question: how many alien vs predator films are there
[{'answer': 'two', 'provenance': [{'wikipedia_id': '511332', 'title': 'Alien vs. Predator (franchise)', 'start_paragraph_id': 1, 'start_character': 260, 'end_paragraph_id': 1, 'end_character': 263, 'bleu_score': 1.0, 'section': 'Section::::Abstract.'}]}]