Question: how many episodes in season 3 of dc legends of tomorrow
[{'answer': '18', 'provenance': [{'wikipedia_id': '51082530', 'title': 'List of Legends of Tomorrow episodes', 'start_paragraph_id': 2, 'start_character': 14, 'end_paragraph_id': 2, 'end_character': 16, 'bleu_score': 1.0, 'section': 'Section::::Abstract.'}]}]