Question: who has written the most number one songs of all time
[{'answer': 'Paul McCartney', 'provenance': [{'wikipedia_id': '640575', 'title': 'Max Martin', 'start_paragraph_id': 2, 'start_character': 382, 'end_paragraph_id': 2, 'end_character': 396, 'bleu_score': 1.0, 'section': 'Section::::Abstract.'}]}, {'provenance': [{'wikipedia_id': '640575', 'title': 'Max Martin', 'start_paragraph_id': 2, 'start_character': 0, 'end_paragraph_id': 2, 'end_character': 421, 'bleu_score': 0.8610009787773951, 'meta': {'yes_no_answer': 'NONE', 'annotation_id': 11529415735085462015}, 'section': 'Section::::Abstract.'}]}]