Question: the minimum number of rings in a piston is
[{'answer': 'two', 'provenance': [{'wikipedia_id': '2796031', 'title': 'Piston ring', 'start_paragraph_id': 7, 'start_character': 164, 'end_paragraph_id': 7, 'end_character': 167, 'bleu_score': 1.0, 'section': 'Section::::Abstract.'}]}, {'provenance': [{'wikipedia_id': '2796031', 'title': 'Piston ring', 'start_paragraph_id': 15, 'start_character': 0, 'end_paragraph_id': 15, 'end_character': 787, 'bleu_score': 0.9719868132454771, 'meta': {'yes_no_answer': 'NONE', 'annotation_id': 16057706101487010347}, 'section': 'Section::::Automotive.\n'}]}]