Question: who attacked first in the battle of chancellorsville
[{'answer': 'Union', 'provenance': [{'wikipedia_id': '48780', 'title': 'Battle of Chancellorsville', 'start_paragraph_id': 1, 'start_character': 371, 'end_paragraph_id': 1, 'end_character': 376, 'bleu_score': 1.0, 'section': 'Section::::Abstract.'}]}, {'provenance': [{'wikipedia_id': '48780', 'title': 'Battle of Chancellorsville', 'start_paragraph_id': 3, 'start_character': 0, 'end_paragraph_id': 3, 'end_character': 557, 'bleu_score': 0.977397480575333, 'meta': {'yes_no_answer': 'NONE', 'annotation_id': 12340530301826071492}, 'section': 'Section::::Abstract.'}]}]