Question: how many rounds did mayweather and guerrero go
[{'answer': '12', 'provenance': [{'wikipedia_id': '38658893', 'title': 'Floyd Mayweather Jr. vs. Robert Guerrero', 'start_paragraph_id': 1, 'start_character': 726, 'end_paragraph_id': 1, 'end_character': 728, 'bleu_score': 1.0, 'section': 'Section::::Abstract.'}]}]