Question: how many counties make up the rio grande valley
[{'answer': 'Hidalgo', 'provenance': [{'wikipedia_id': '604689', 'title': 'Rio Grande Valley', 'start_paragraph_id': 1, 'start_character': 214, 'end_paragraph_id': 1, 'end_character': 221, 'bleu_score': 1.0, 'section': 'Section::::Abstract.'}]}, {'answer': 'Cameron', 'provenance': [{'wikipedia_id': '604689', 'title': 'Rio Grande Valley', 'start_paragraph_id': 1, 'start_character': 223, 'end_paragraph_id': 1, 'end_character': 230, 'bleu_score': 1.0, 'section': 'Section::::Abstract.'}]}, {'answer': 'Willacy', 'provenance': [{'wikipedia_id': '604689', 'title': 'Rio Grande Valley', 'start_paragraph_id': 1, 'start_character': 232, 'end_paragraph_id': 1, 'end_character': 239, 'bleu_score': 1.0, 'section': 'Section::::Abstract.'}]}, {'answer': 'Starr', 'provenance': [{'wikipedia_id': '604689', 'title': 'Rio Grande Valley', 'start_paragraph_id': 1, 'start_character': 245, 'end_paragraph_id': 1, 'end_character': 250, 'bleu_score': 1.0, 'section': 'Section::::Abstract.'}]}, {'provenance': [{'wikipedia_id': '604689', 'title': 'Rio Grande Valley', 'start_paragraph_id': 1, 'start_character': 0, 'end_paragraph_id': 1, 'end_character': 429, 'bleu_score': 0.5466689208055331, 'meta': {'yes_no_answer': 'NONE', 'annotation_id': 5844444794035462482}, 'section': 'Section::::Abstract.'}]}]