Question: who has won the champions league/european cup the most times
[{'answer': 'Real Madrid', 'provenance': [{'wikipedia_id': '2947751', 'title': 'List of European Cup and UEFA Champions League finals', 'start_paragraph_id': 2, 'start_character': 162, 'end_paragraph_id': 2, 'end_character': 173, 'bleu_score': 1.0, 'section': 'Section::::Abstract.'}]}]