Question: how many aircraft carriers does us navy have
[{'answer': 'ten', 'provenance': [{'wikipedia_id': '203196', 'title': 'List of aircraft carriers of the United States Navy', 'start_paragraph_id': 3, 'start_character': 168, 'end_paragraph_id': 3, 'end_character': 171, 'bleu_score': 1.0, 'section': 'Section::::Abstract.'}]}, {'provenance': [{'wikipedia_id': '203196', 'title': 'List of aircraft carriers of the United States Navy', 'start_paragraph_id': 5, 'start_character': 0, 'end_paragraph_id': 5, 'end_character': 518, 'bleu_score': 0.5516341377481131, 'meta': {'yes_no_answer': 'NONE', 'annotation_id': 14585336703267647930}, 'section': 'Section::::Abstract.'}]}]