Question: how many countries are there in northern america
[{'answer': '23', 'provenance': [{'wikipedia_id': '21139', 'title': 'North America', 'start_paragraph_id': 3, 'start_character': 212, 'end_paragraph_id': 3, 'end_character': 214, 'bleu_score': 1.0, 'section': 'Section::::Abstract.'}]}]