Question: how many letter are in the arabic alphabet
[{'answer': '28', 'provenance': [{'wikipedia_id': '2204', 'title': 'Arabic alphabet', 'start_paragraph_id': 1, 'start_character': 171, 'end_paragraph_id': 1, 'end_character': 173, 'bleu_score': 1.0, 'section': 'Section::::Abstract.'}]}, {'provenance': [{'wikipedia_id': '2204', 'title': 'Arabic alphabet', 'start_paragraph_id': 1, 'start_character': 0, 'end_paragraph_id': 1, 'end_character': 181, 'bleu_score': 0.5506585289732501, 'meta': {'yes_no_answer': 'NONE', 'annotation_id': 6765624836008048215}, 'section': 'Section::::Abstract.'}]}]