Question: who was the first elected president of pakistan
[{'answer': 'Iskander Mirza', 'provenance': [{'wikipedia_id': '461863', 'title': 'List of Presidents of Pakistan', 'start_paragraph_id': 2, 'start_character': 208, 'end_paragraph_id': 2, 'end_character': 222, 'bleu_score': 1.0, 'section': 'Section::::Abstract.'}]}, {'answer': 'JB Talha Khan'}, {'provenance': [{'wikipedia_id': '461863', 'title': 'List of Presidents of Pakistan', 'start_paragraph_id': 2, 'start_character': 0, 'end_paragraph_id': 2, 'end_character': 688, 'bleu_score': 0.8504738462686681, 'meta': {'yes_no_answer': 'NONE', 'annotation_id': 404219142297196122}, 'section': 'Section::::Abstract.'}]}, {'provenance': [{'wikipedia_id': '461863', 'title': 'List of Presidents of Pakistan', 'section': 'Section::::Abstract.', 'start_paragraph_id': 2, 'end_paragraph_id': 2, 'meta': {'evidence_span': ['Iskander Mirza became the first president of the country.', 'The office was established when Pakistan was declared as a republic with the adoption of the 1956 constitution, and Iskander Mirza became the first president of the country.', 'There have been thirteen presidents of Pakistan since the introduction of the post in 1956. The office was established when Pakistan was declared as a republic with the adoption of the 1956 constitution, and Iskander Mirza became the first president of the country']}}]}]