Question: who has won back to back champions league
[{'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.'}]}, {'answer': 'Benfica'}, {'answer': 'Internazionale'}, {'answer': 'Ajax', 'provenance': [{'wikipedia_id': '2947751', 'title': 'List of European Cup and UEFA Champions League finals', 'start_paragraph_id': 2, 'start_character': 175, 'end_paragraph_id': 2, 'end_character': 179, 'bleu_score': 1.0, 'section': 'Section::::Abstract.'}]}, {'answer': 'Bayern Munich', 'provenance': [{'wikipedia_id': '2947751', 'title': 'List of European Cup and UEFA Champions League finals', 'start_paragraph_id': 2, 'start_character': 181, 'end_paragraph_id': 2, 'end_character': 194, 'bleu_score': 1.0, 'section': 'Section::::Abstract.'}]}, {'answer': 'Liverpool', 'provenance': [{'wikipedia_id': '2947751', 'title': 'List of European Cup and UEFA Champions League finals', 'start_paragraph_id': 1, 'start_character': 841, 'end_paragraph_id': 1, 'end_character': 850, 'bleu_score': 1.0, 'section': 'Section::::Abstract.'}]}, {'answer': 'Nottingham Forest'}, {'answer': 'Milan', 'provenance': [{'wikipedia_id': '2947751', 'title': 'List of European Cup and UEFA Champions League finals', 'start_paragraph_id': 2, 'start_character': 196, 'end_paragraph_id': 2, 'end_character': 201, 'bleu_score': 1.0, 'section': 'Section::::Abstract.'}]}]