Which actor has acted in the most movies?
{'directed': True, 'multigraph': False, 'graph': {}, 'nodes': [{'type': 'QUESTIONS_ENTITY', 'name_': 'Q11424', 'id': 0, 'label': 'film'}, {'type': 'QUESTIONS_ENTITY', 'name_': 'Q33999', 'id': 1, 'label': 'actor'}, {'type': 'INTERNAL', 'name_': 'Q853', 'id': 2, 'label': 'Andrei Tarkovsky'}, {'type': 'INTERNAL', 'name_': 'Q179', 'id': 3, 'label': 'Boeing 747'}], 'links': [{'name_': 'P1963', 'source': 0, 'target': 3, 'label': 'properties for this type'}, {'name_': 'P101', 'source': 2, 'target': 0, 'label': 'field of work'}, {'name_': 'P106', 'source': 2, 'target': 1, 'label': 'occupation'}]}