Question: when did the little rock nine integrate central high school
[{'answer': '1957', 'provenance': [{'wikipedia_id': '20329639', 'title': 'Little Rock Nine', 'start_paragraph_id': 1, 'start_character': 114, 'end_paragraph_id': 1, 'end_character': 118, 'bleu_score': 1.0, 'section': 'Section::::Abstract.'}]}, {'provenance': [{'wikipedia_id': '20329639', 'title': 'Little Rock Nine', 'start_paragraph_id': 1, 'start_character': 0, 'end_paragraph_id': 1, 'end_character': 387, 'bleu_score': 0.96746874041754, 'meta': {'yes_no_answer': 'NONE', 'annotation_id': 17519176443238804774}, 'section': 'Section::::Abstract.'}]}]