Question: who was the first president of the constituent assembly
[{'answer': 'Dr. Rajendra Prasad', 'provenance': [{'wikipedia_id': '1589530', 'title': 'Constituent Assembly of India', 'start_paragraph_id': 15, 'start_character': 91, 'end_paragraph_id': 15, 'end_character': 110, 'bleu_score': 1.0, 'section': 'Section::::Organization.\n'}]}, {'provenance': [{'wikipedia_id': '1589530', 'title': 'Constituent Assembly of India', 'start_paragraph_id': 15, 'start_character': 0, 'end_paragraph_id': 15, 'end_character': 615, 'bleu_score': 0.884067445879755, 'meta': {'yes_no_answer': 'NONE', 'annotation_id': 4757313740904987392}, 'section': 'Section::::Organization.\n'}]}, {'provenance': [{'wikipedia_id': '1589530', 'title': 'Constituent Assembly of India', 'start_paragraph_id': 0, 'start_character': 0, 'end_paragraph_id': 0, 'end_character': 0, 'bleu_score': 1.0, 'meta': {'yes_no_answer': 'NONE', 'annotation_id': 4757313740904987392}, 'section': 'Section::::Abstract.'}]}, {'provenance': [{'wikipedia_id': '290769', 'title': 'List of presidents of India', 'section': 'Section::::Abstract.', 'start_paragraph_id': 3, 'end_paragraph_id': 3, 'meta': {'evidence_span': ['There have been 14 presidents of India since the post was established when India was declared as a republic with the adoption of the Indian constitution in 1950. Apart from these fourteen, three acting presidents have also been in office for short periods of time. Varahagiri Venkata Giri became the acting president in 1969 after Zakir Husain, died in office. Giri was elected president a few months later. He remains the only person to have held office both as a president and acting president. Rajendra Prasad, the first president of India, is the only person to have held office for two terms.', 'Rajendra Prasad, the first president of India, is the only person to have held office for two terms.', 'Rajendra Prasad, the first president of India, is the only person to have held office for two terms.']}}]}, {'provenance': [{'wikipedia_id': '1589530', 'title': 'Constituent Assembly of India', 'section': 'Section::::Organization.\n', 'start_paragraph_id': 15, 'end_paragraph_id': 15, 'meta': {'evidence_span': ["Dr. Sachchidananda Sinha was the first chairman (temporary) of Constituent Assembly. Later Dr. Rajendra Prasad was elected as the president and Its vice-president was Harendra Coomar Mookerjee, a Christian from Bengal and former vice-chancellor of Calcutta University. Also chairing the assembly's Minorities Committee, Mookerjee was appointed governor of West Bengal after India became a republic. Jurist B. N. Rau was appointed constitutional adviser to the assembly; Rau prepared the original draft of the constitution, and was later appointed a judge in the Permanent Court of International Justice in The Hague.", 'Dr. Sachchidananda Sinha was the first chairman (temporary) of Constituent Assembly. Later Dr. Rajendra Prasad was elected as the president']}}]}]