Question: how many african american politicians served in the us congress during reconstruction
[{'answer': 'Two', 'provenance': [{'wikipedia_id': '391889', 'title': 'African Americans in the United States Congress', 'start_paragraph_id': 5, 'start_character': 84, 'end_paragraph_id': 5, 'end_character': 87, 'bleu_score': 1.0, 'section': 'Section::::Abstract.'}]}, {'provenance': [{'wikipedia_id': '391889', 'title': 'African Americans in the United States Congress', 'start_paragraph_id': 5, 'start_character': 0, 'end_paragraph_id': 5, 'end_character': 427, 'bleu_score': 0.968982777549629, 'meta': {'yes_no_answer': 'NONE', 'annotation_id': 8860987076659904597}, 'section': 'Section::::Abstract.'}]}]