Question: who has the most submission wins in ufc history
[{'answer': 'Royce Gracie', 'provenance': [{'wikipedia_id': '48958073', 'title': 'List of UFC records', 'start_paragraph_id': 6, 'start_character': 22, 'end_paragraph_id': 6, 'end_character': 34, 'bleu_score': 1.0, 'section': 'Section::::Fighting.:Most bouts.:In any bout.:All fighters.\n'}]}]