Question: who is the only leader to be elected prime minister of pakistan three times
[{'answer': 'Nawaz Sharif', 'provenance': [{'wikipedia_id': '461902', 'title': 'List of Prime Ministers of Pakistan', 'start_paragraph_id': 3, 'start_character': 941, 'end_paragraph_id': 3, 'end_character': 953, 'bleu_score': 1.0, 'section': 'Section::::Abstract.'}]}]