Question: how many volumes of mirai nikki are there
[{'answer': 'Twelve'}, {'provenance': [{'wikipedia_id': '11809077', 'title': 'Future Diary', 'start_paragraph_id': 1, 'start_character': 0, 'end_paragraph_id': 1, 'end_character': 518, 'bleu_score': 0.5390418198479651, 'meta': {'yes_no_answer': 'NONE', 'annotation_id': 12971506593283434890}, 'section': 'Section::::Abstract.'}]}]