Question: which city is the first in the world to be awarded both summer and winter olympics
[{'answer': 'Beijing', 'provenance': [{'wikipedia_id': '11015817', 'title': 'List of Olympic Games host cities', 'start_paragraph_id': 3, 'start_character': 108, 'end_paragraph_id': 3, 'end_character': 115, 'bleu_score': 1.0, 'section': 'Section::::Abstract.'}]}]