Question: how many brands of e cigarettes are there
[{'answer': 'more than 460', 'provenance': [{'wikipedia_id': '51917319', 'title': 'List of electronic cigarette and e-cigarette liquid brands', 'start_paragraph_id': 1, 'start_character': 83, 'end_paragraph_id': 1, 'end_character': 96, 'bleu_score': 1.0, 'section': 'Section::::Abstract.'}]}]