Question: how many episode is ruler master of the mask
[{'answer': '40', 'provenance': [{'wikipedia_id': '51990351', 'title': 'The Emperor: Owner of the Mask', 'start_paragraph_id': 1, 'start_character': 247, 'end_paragraph_id': 1, 'end_character': 249, 'bleu_score': 1.0, 'section': 'Section::::Abstract.'}]}, {'provenance': [{'wikipedia_id': '51990351', 'title': 'The Emperor: Owner of the Mask', 'start_paragraph_id': 1, 'start_character': 0, 'end_paragraph_id': 1, 'end_character': 258, 'bleu_score': 0.7352469216079041, 'meta': {'yes_no_answer': 'NONE', 'annotation_id': 14873974385245456696}, 'section': 'Section::::Abstract.'}]}]