Question: what year did the cowboys and steelers play in the super bowl
[{'answer': '1976'}, {'answer': '1979', 'provenance': [{'wikipedia_id': '26565584', 'title': 'Cowboys–Steelers rivalry', 'start_paragraph_id': 18, 'start_character': 16, 'end_paragraph_id': 18, 'end_character': 20, 'bleu_score': 1.0, 'section': 'Section::::History.:1960–1969: Early years.\n'}]}, {'answer': '1996', 'provenance': [{'wikipedia_id': '26565584', 'title': 'Cowboys–Steelers rivalry', 'start_paragraph_id': 32, 'start_character': 264, 'end_paragraph_id': 32, 'end_character': 268, 'bleu_score': 1.0, 'section': 'Section::::History.:1990–present: Return to prominence.\n'}]}]