Question: how many states is there in united states
[{'answer': '50', 'provenance': [{'wikipedia_id': '3434750', 'title': 'United States', 'start_paragraph_id': 1, 'start_character': 121, 'end_paragraph_id': 1, 'end_character': 123, 'bleu_score': 1.0, 'section': 'Section::::Abstract.'}]}]