Question: what was russia called after the russian revolution
[{'answer': 'the Soviet Union', 'provenance': [{'wikipedia_id': '25762', 'title': 'Russian Revolution', 'start_paragraph_id': 1, 'start_character': 201, 'end_paragraph_id': 1, 'end_character': 217, 'bleu_score': 1.0, 'section': 'Section::::Abstract.'}]}]