Question: name of the three headed dog in greek mythology
[{'answer': 'Cerberus', 'provenance': [{'wikipedia_id': '6697', 'title': 'Cerberus', 'start_paragraph_id': 0, 'start_character': 0, 'end_paragraph_id': 0, 'end_character': 8, 'bleu_score': 1.0, 'section': 'Section::::Abstract.'}]}, {'provenance': [{'wikipedia_id': '6697', 'title': 'Cerberus', 'start_paragraph_id': 1, 'start_character': 0, 'end_paragraph_id': 1, 'end_character': 453, 'bleu_score': 0.7758005600797591, 'meta': {'yes_no_answer': 'NONE', 'annotation_id': 17941808633268068253}, 'section': 'Section::::Abstract.'}]}]