Question: what is the thirteenth letter in the alphabet
[{'answer': 'M', 'provenance': [{'wikipedia_id': '19191', 'title': 'M', 'start_paragraph_id': 0, 'start_character': 0, 'end_paragraph_id': 0, 'end_character': 1, 'bleu_score': 1.0, 'section': 'Section::::Abstract.'}]}, {'provenance': [{'wikipedia_id': '19191', 'title': 'M', 'start_paragraph_id': 1, 'start_character': 0, 'end_paragraph_id': 1, 'end_character': 104, 'bleu_score': 0.7618274083334161, 'meta': {'yes_no_answer': 'NONE', 'annotation_id': 6017303238214078177}, 'section': 'Section::::Abstract.'}]}]