How many people have won the title on American Ninja Warrior?
{'directed': True, 'multigraph': False, 'graph': {}, 'nodes': [{'type': 'INTERNAL', 'name_': 'Q6173448', 'id': 0, 'label': 'Wikipedia:Vital articles/Level/4'}, {'type': 'INTERNAL', 'name_': 'Q30', 'id': 1, 'label': 'United States of America'}, {'type': 'INTERNAL', 'name_': 'Q4167836', 'id': 2, 'label': 'Wikimedia category'}, {'type': 'ANSWER_CANDIDATE_ENTITY', 'name_': 'Q199', 'id': 3, 'label': '1'}, {'type': 'INTERNAL', 'name_': 'Q25061924', 'id': 4, 'label': 'Category:American Ninja Warrior'}, {'type': 'QUESTIONS_ENTITY', 'name_': 'Q4744595', 'id': 5, 'label': 'American Ninja Warrior'}, {'type': 'INTERNAL', 'name_': 'Q8485348', 'id': 6, 'label': 'Category:1 (number)'}, {'type': 'INTERNAL', 'name_': 'Q102271484', 'id': 7, 'label': 'David Burnell IV'}], 'links': [{'name_': 'P5008', 'source': 1, 'target': 0, 'label': 'on focus list of Wikimedia project'}, {'name_': 'P17', 'source': 1, 'target': 1, 'label': 'country'}, {'name_': 'P5008', 'source': 3, 'target': 0, 'label': 'on focus list of Wikimedia project'}, {'name_': 'P8865', 'source': 3, 'target': 3, 'label': 'mathematical inverse'}, {'name_': 'P910', 'source': 3, 'target': 6, 'label': "topic's main category"}, {'name_': 'P31', 'source': 4, 'target': 2, 'label': 'instance of'}, {'name_': 'P301', 'source': 4, 'target': 5, 'label': "category's main topic"}, {'name_': 'P31', 'source': 6, 'target': 2, 'label': 'instance of'}, {'name_': 'P301', 'source': 6, 'target': 3, 'label': "category's main topic"}, {'name_': 'P27', 'source': 7, 'target': 1, 'label': 'country of citizenship'}, {'name_': 'P800', 'source': 7, 'target': 5, 'label': 'notable work'}]}