Question: when did the nba change the first round of playoffs to 7 games
[{'answer': '2003', 'provenance': [{'wikipedia_id': '12106552', 'title': 'NBA playoffs', 'start_paragraph_id': 12, 'start_character': 169, 'end_paragraph_id': 12, 'end_character': 173, 'bleu_score': 1.0, 'section': 'Section::::History.\n'}]}]