How many countries are in South Asia?
{'directed': True, 'multigraph': False, 'graph': {}, 'nodes': [{'type': 'QUESTIONS_ENTITY', 'name_': 'Q771405', 'id': 0, 'label': 'South Asia'}, {'type': 'ANSWER_CANDIDATE_ENTITY', 'name_': 'Q106020289', 'id': 1, 'label': 'economy of South Asia'}], 'links': [{'name_': 'P8744', 'source': 0, 'target': 1, 'label': 'economy of topic'}]}