Question: how many episodes in the tunnel series 2
[{'answer': '8', 'provenance': [{'wikipedia_id': '42544324', 'title': 'List of The Tunnel episodes', 'start_paragraph_id': 4, 'start_character': 255, 'end_paragraph_id': 4, 'end_character': 256, 'bleu_score': 1.0, 'section': 'Section::::Abstract.'}]}]