Question: when did the beatles perform at shea stadium
[{'answer': '15 August 1965', 'provenance': [{'wikipedia_id': '19738230', 'title': 'The Beatles at Shea Stadium', 'start_paragraph_id': 1, 'start_character': 79, 'end_paragraph_id': 1, 'end_character': 93, 'bleu_score': 1.0, 'section': 'Section::::Abstract.'}]}, {'provenance': [{'wikipedia_id': '19738230', 'title': 'The Beatles at Shea Stadium', 'start_paragraph_id': 1, 'start_character': 0, 'end_paragraph_id': 1, 'end_character': 782, 'bleu_score': 0.9488154124909641, 'meta': {'yes_no_answer': 'NONE', 'annotation_id': 16654801185707901961}, 'section': 'Section::::Abstract.'}]}]