Which president was younger when he took office, Kennedy or Obama?
{'directed': True, 'multigraph': False, 'graph': {}, 'nodes': [{'type': 'INTERNAL', 'name_': 'Q30', 'id': 0, 'label': 'United States of America'}, {'type': 'INTERNAL', 'name_': 'Q567', 'id': 1, 'label': 'Angela Merkel'}, {'type': 'QUESTIONS_ENTITY', 'name_': 'Q9696', 'id': 2, 'label': 'John F. Kennedy'}, {'type': 'ANSWER_CANDIDATE_ENTITY', 'name_': 'Q207826', 'id': 3, 'label': 'Time Person of the Year'}, {'type': 'QUESTIONS_ENTITY', 'name_': 'Q76', 'id': 4, 'label': 'Barack Obama'}, {'type': 'INTERNAL', 'name_': 'Q83502', 'id': 5, 'label': '2012 NATO Summit in Chicago'}], 'links': [{'name_': 'P17', 'source': 0, 'target': 0, 'label': 'country'}, {'name_': 'P6', 'source': 0, 'target': 2, 'label': 'head of government'}, {'name_': 'P6', 'source': 0, 'target': 4, 'label': 'head of government'}, {'name_': 'P166', 'source': 1, 'target': 3, 'label': 'award received'}, {'name_': 'P27', 'source': 2, 'target': 0, 'label': 'country of citizenship'}, {'name_': 'P166', 'source': 2, 'target': 3, 'label': 'award received'}, {'name_': 'P17', 'source': 5, 'target': 0, 'label': 'country'}, {'name_': 'P710', 'source': 5, 'target': 1, 'label': 'participant'}, {'name_': 'P710', 'source': 5, 'target': 4, 'label': 'participant'}]}