Question: who has played in the most nba finals games
[{'answer': 'Bill Russell', 'provenance': [{'wikipedia_id': '890793', 'title': 'NBA Finals', 'start_paragraph_id': 8, 'start_character': 76, 'end_paragraph_id': 8, 'end_character': 88, 'bleu_score': 1.0, 'section': 'Section::::History.:1957–1969: Celtics dynasty.\n'}]}]