Question: who became the first president of the bharti janta party when it was formally established
[{'answer': 'Vajpayee', 'provenance': [{'wikipedia_id': '149330', 'title': 'Bharatiya Janata Party', 'start_paragraph_id': 3, 'start_character': 136, 'end_paragraph_id': 3, 'end_character': 144, 'bleu_score': 1.0, 'section': 'Section::::Abstract.'}]}, {'provenance': [{'wikipedia_id': '149330', 'title': 'Bharatiya Janata Party', 'start_paragraph_id': 17, 'start_character': 0, 'end_paragraph_id': 17, 'end_character': 764, 'bleu_score': 0.984789766484456, 'meta': {'yes_no_answer': 'NONE', 'annotation_id': 2391910143636747207}, 'section': 'Section::::History.:BJP (1980–present).:Formation and early days.\n'}]}]