How many games are in the Mafia series?
{'directed': True, 'multigraph': False, 'graph': {}, 'nodes': [{'type': 'ANSWER_CANDIDATE_ENTITY', 'name_': 'Q213', 'id': 0, 'label': 'Czech Republic'}, {'type': 'QUESTIONS_ENTITY', 'name_': 'Q213217', 'id': 1, 'label': 'Mafia'}, {'type': 'INTERNAL', 'name_': 'Q71192266', 'id': 2, 'label': 'Mafia Triple Pack'}], 'links': [{'name_': 'P17', 'source': 0, 'target': 0, 'label': 'country'}, {'name_': 'P495', 'source': 2, 'target': 0, 'label': 'country of origin'}, {'name_': 'P527', 'source': 2, 'target': 1, 'label': 'has part(s)'}]}