Question: how many helicopters did the soviets lose in afghanistan
[{'answer': 'at least 333 helicopters', 'provenance': [{'wikipedia_id': '4617382', 'title': 'List of Soviet aircraft losses during the Soviet–Afghan War', 'start_paragraph_id': 1, 'start_character': 147, 'end_paragraph_id': 1, 'end_character': 171, 'bleu_score': 1.0, 'section': 'Section::::Abstract.'}]}]