Question: how many episodes of season 8 blue bloods
[{'answer': '22', 'provenance': [{'wikipedia_id': '55391826', 'title': 'Blue Bloods (season 8)', 'start_paragraph_id': 1, 'start_character': 175, 'end_paragraph_id': 1, 'end_character': 177, 'bleu_score': 1.0, 'section': 'Section::::Abstract.'}]}]