Question: how many episodes are in crisis on earth x
[{'answer': 'four', 'provenance': [{'wikipedia_id': '54799795', 'title': 'Crisis on Earth-X', 'start_paragraph_id': 1, 'start_character': 27, 'end_paragraph_id': 1, 'end_character': 31, 'bleu_score': 1.0, 'section': 'Section::::Abstract.'}]}, {'provenance': [{'wikipedia_id': '54799795', 'title': 'Crisis on Earth-X', 'start_paragraph_id': 34, 'start_character': 0, 'end_paragraph_id': 34, 'end_character': 206, 'bleu_score': 0.5810419951447441, 'meta': {'yes_no_answer': 'NONE', 'annotation_id': 16317745165565247895}, 'section': 'Section::::Production.:Filming.\n'}]}]