Question: who sang in the halftime show last year
[{'answer': 'Lady Gaga', 'provenance': [{'wikipedia_id': '1730307', 'title': 'List of Super Bowl halftime shows', 'start_paragraph_id': 1, 'start_character': 758, 'end_paragraph_id': 1, 'end_character': 767, 'bleu_score': 1.0, 'section': 'Section::::Abstract.'}]}]