Question: how many times do teams play each other in the nba playoffs
[{'answer': 'best - of - seven', 'provenance': [{'wikipedia_id': '12106552', 'title': 'NBA playoffs', 'start_paragraph_id': 12, 'start_character': 213, 'end_paragraph_id': 12, 'end_character': 227, 'bleu_score': 1.0, 'section': 'Section::::History.\n'}]}, {'provenance': [{'wikipedia_id': '12106552', 'title': 'NBA playoffs', 'start_paragraph_id': 1, 'start_character': 0, 'end_paragraph_id': 1, 'end_character': 173, 'bleu_score': 0.864570730155636, 'meta': {'yes_no_answer': 'NONE', 'annotation_id': 7252380216381675466}, 'section': 'Section::::Abstract.'}]}]