Question: when did seattle slew win the triple crown
[{'answer': '1977', 'provenance': [{'wikipedia_id': '465736', 'title': 'Seattle Slew', 'start_paragraph_id': 1, 'start_character': 115, 'end_paragraph_id': 1, 'end_character': 119, 'bleu_score': 1.0, 'section': 'Section::::Abstract.'}]}, {'answer': 'in 1977', 'provenance': [{'wikipedia_id': '465736', 'title': 'Seattle Slew', 'start_paragraph_id': 1, 'start_character': 112, 'end_paragraph_id': 1, 'end_character': 119, 'bleu_score': 1.0, 'section': 'Section::::Abstract.'}]}, {'provenance': [{'wikipedia_id': '465736', 'title': 'Seattle Slew', 'start_paragraph_id': 1, 'start_character': 13, 'end_paragraph_id': 1, 'end_character': 581, 'bleu_score': 0.697725878255118, 'meta': {'yes_no_answer': 'NONE', 'annotation_id': 5520740745025712999}, 'section': 'Section::::Abstract.'}]}, {'provenance': [{'wikipedia_id': '465736', 'title': 'Seattle Slew', 'section': 'Section::::Abstract.', 'start_paragraph_id': 1, 'end_paragraph_id': 1, 'meta': {'evidence_span': ['Seattle Slew (February 15, 1974 May 7, 2002) was an American Thoroughbred race horse who won the Triple Crown in 1977', 'Seattle Slew (February 15, 1974 May 7, 2002) was an American Thoroughbred race horse who won the Triple Crown in 1977 the tenth of thirteen horses to accomplish the feat. He is one of two horses to have won the Triple Crown while having been undefeated in any previous race; the second was Justify, who won the Triple Crown in 2018 and who is descended from Seattle Slew. Honored as the 1977 Horse of the Year, he was also a champion at ages two, three, and four. In the Blood-Horse magazine List of the Top 100 U.S. Racehorses of the 20th Century Seattle Slew was ranked ninth.']}}]}, {'provenance': [{'wikipedia_id': '31748503', 'title': 'Seattle Song', 'section': 'Section::::Abstract.', 'start_paragraph_id': 1, 'end_paragraph_id': 1, 'meta': {'evidence_span': ['Seattle Song (February 19, 1981 February 3, 1996) was a French Thoroughbred racehorse who won the 1983 Prix de la Salamandre under American jockey Cash Asmussen and who visited the United States in October 1984,', 'Seattle Song (February 19, 1981 February 3, 1996) was a French Thoroughbred racehorse who won the 1983 Prix de la Salamandre under American jockey Cash Asmussen and who visited the United States in October 1984, where he won the prestigious Washington, D.C. International Stakes. Bred in Kentucky, Seattle Song was sired by 1977 U.S. Triple Crown winner Seattle Slew. He was out of the mare Incantation, who was sired by Prince Blessed, winner of the 1961 Hollywood Gold Cup and American Handicap. He was selected by trainer']}}]}]