Question: when was the last time the browns were in the super bowl
[{'answer': '1964', 'provenance': [{'wikipedia_id': '6576', 'title': 'Cleveland Browns', 'start_paragraph_id': 2, 'start_character': 534, 'end_paragraph_id': 2, 'end_character': 538, 'bleu_score': 1.0, 'section': 'Section::::Abstract.'}]}]