Question: who has won more titles federer or nadal
[{'answer': 'Federer', 'provenance': [{'wikipedia_id': '17271235', 'title': 'Federer–Nadal rivalry', 'start_paragraph_id': 0, 'start_character': 0, 'end_paragraph_id': 0, 'end_character': 7, 'bleu_score': 1.0, 'section': 'Section::::Abstract.'}]}, {'provenance': [{'wikipedia_id': '17271235', 'title': 'Federer–Nadal rivalry', 'start_paragraph_id': 3, 'start_character': 53, 'end_paragraph_id': 3, 'end_character': 770, 'bleu_score': 0.7684773496613411, 'meta': {'yes_no_answer': 'NONE', 'annotation_id': 10042371469957070556}, 'section': 'Section::::Abstract.'}]}]