Question: when did the navajo arrive in the southwest
[{'answer': '1400 CE', 'provenance': [{'wikipedia_id': '3007285', 'title': 'Navajo', 'start_paragraph_id': 8, 'start_character': 127, 'end_paragraph_id': 8, 'end_character': 134, 'bleu_score': 1.0, 'section': 'Section::::History.:Early history.\n'}]}, {'provenance': [{'wikipedia_id': '3007285', 'title': 'Navajo', 'start_paragraph_id': 8, 'start_character': 0, 'end_paragraph_id': 8, 'end_character': 208, 'bleu_score': 0.7228510654654651, 'meta': {'yes_no_answer': 'NONE', 'annotation_id': 8839850695544359268}, 'section': 'Section::::History.:Early history.\n'}]}]