Question: who has performed the most at madison square garden
[{'answer': 'Billy Joel', 'provenance': [{'wikipedia_id': '75129', 'title': 'Madison Square Garden', 'start_paragraph_id': 38, 'start_character': 829, 'end_paragraph_id': 38, 'end_character': 839, 'bleu_score': 1.0, 'section': 'Section::::Events.:Regular events.:Concerts.\n'}]}, {'provenance': [{'wikipedia_id': '75129', 'title': 'Madison Square Garden', 'start_paragraph_id': 39, 'start_character': 0, 'end_paragraph_id': 39, 'end_character': 724, 'bleu_score': 0.9850176677359421, 'meta': {'yes_no_answer': 'NONE', 'annotation_id': 5572364356379718396}, 'section': 'Section::::Events.:Regular events.:Concerts.\n'}]}]