Question: how many seasons of happy days are on dvd
[{'answer': 'six', 'provenance': [{'wikipedia_id': '171103', 'title': 'Happy Days', 'start_paragraph_id': 120, 'start_character': 65, 'end_paragraph_id': 120, 'end_character': 68, 'bleu_score': 1.0, 'section': 'Section::::Home media.\n'}]}, {'provenance': [{'wikipedia_id': '171103', 'title': 'Happy Days', 'start_paragraph_id': 120, 'start_character': 0, 'end_paragraph_id': 120, 'end_character': 527, 'bleu_score': 0.7060819623181841, 'meta': {'yes_no_answer': 'NONE', 'annotation_id': 10516090764416432937}, 'section': 'Section::::Home media.\n'}]}]