Question: when did the first episode of mash aired
[{'answer': 'September 17 , 1972', 'provenance': [{'wikipedia_id': '156045', 'title': 'M*A*S*H (TV series)', 'start_paragraph_id': 57, 'start_character': 34, 'end_paragraph_id': 57, 'end_character': 53, 'bleu_score': 1.0, 'section': 'Section::::Reception.:Ratings and recognition.\n'}]}]