Question: what is the length of year on mars
[{'answer': 'about 686.98 Earth solar days', 'provenance': [{'wikipedia_id': '1784050', 'title': 'Timekeeping on Mars', 'start_paragraph_id': 32, 'start_character': 94, 'end_paragraph_id': 32, 'end_character': 123, 'bleu_score': 1.0, 'section': 'Section::::Years.\n'}]}, {'provenance': [{'wikipedia_id': '1784050', 'title': 'Timekeeping on Mars', 'start_paragraph_id': 32, 'start_character': 0, 'end_paragraph_id': 32, 'end_character': 549, 'bleu_score': 0.7612934896156901, 'meta': {'yes_no_answer': 'NONE', 'annotation_id': 14321602607040543004}, 'section': 'Section::::Years.\n'}]}]