Question: how many times have barcelona won uefa champions league
[{'answer': '5', 'provenance': [{'wikipedia_id': '2947751', 'title': 'List of European Cup and UEFA Champions League finals', 'start_paragraph_id': 1, 'start_character': 78, 'end_paragraph_id': 1, 'end_character': 79, 'bleu_score': 1.0, 'section': 'Section::::Abstract.'}]}]