Question: how many pitches do musicians have to work with in the western musical system of today
[{'answer': '12', 'provenance': [{'wikipedia_id': '20201', 'title': 'Musical notation', 'start_paragraph_id': 7, 'start_character': 337, 'end_paragraph_id': 7, 'end_character': 339, 'bleu_score': 1.0, 'section': 'Section::::History.:Ancient Near East.\n'}]}, {'provenance': [{'wikipedia_id': '20201', 'title': 'Musical notation', 'start_paragraph_id': 94, 'start_character': 0, 'end_paragraph_id': 94, 'end_character': 943, 'bleu_score': 0.985964042079227, 'meta': {'yes_no_answer': 'NONE', 'annotation_id': 8684267279778208585}, 'section': 'Section::::Other systems and practices.:Chromatic staff notations.\n'}]}]