Question: what allied nation was the first to reach the german capitol of berlin
[{'answer': 'Soviet Union', 'provenance': [{'wikipedia_id': '1688400', 'title': 'Race to Berlin', 'start_paragraph_id': 13, 'start_character': 634, 'end_paragraph_id': 13, 'end_character': 646, 'bleu_score': 1.0, 'section': 'Section::::From the east.\n'}]}]