Question: how many sirens were there in the odyssey
[{'answer': 'two', 'provenance': [{'wikipedia_id': '51017', 'title': 'Siren (mythology)', 'start_paragraph_id': 12, 'start_character': 43, 'end_paragraph_id': 12, 'end_character': 46, 'bleu_score': 1.0, 'section': 'Section::::List of Sirens.\n'}]}, {'provenance': [{'wikipedia_id': '51017', 'title': 'Siren (mythology)', 'start_paragraph_id': 12, 'start_character': 0, 'end_paragraph_id': 12, 'end_character': 918, 'bleu_score': 0.6907170541156571, 'meta': {'yes_no_answer': 'NONE', 'annotation_id': 10813760687371942787}, 'section': 'Section::::List of Sirens.\n'}]}]