Question: who was the soviet premier when the soviet union collapsed in 1991 formally ending the cold war
[{'answer': 'Valentin Pavlov', 'provenance': [{'wikipedia_id': '40494892', 'title': 'Dissolution of the Soviet Union', 'start_paragraph_id': 178, 'start_character': 154, 'end_paragraph_id': 178, 'end_character': 169, 'bleu_score': 1.0, 'section': "Section::::1991.:Moscow's crisis.\n"}]}, {'provenance': [{'wikipedia_id': '40494892', 'title': 'Dissolution of the Soviet Union', 'start_paragraph_id': 178, 'start_character': 0, 'end_paragraph_id': 178, 'end_character': 237, 'bleu_score': 0.9517713210466091, 'meta': {'yes_no_answer': 'NONE', 'annotation_id': 15229138564252497310}, 'section': "Section::::1991.:Moscow's crisis.\n"}]}]