Question: what was the first hotel built in las vegas
[{'answer': 'El Rancho Vegas', 'provenance': [{'wikipedia_id': '447621', 'title': 'Las Vegas Strip', 'start_paragraph_id': 12, 'start_character': 137, 'end_paragraph_id': 12, 'end_character': 152, 'bleu_score': 1.0, 'section': 'Section::::History.:Early years (1930s–1990s).\n'}]}, {'provenance': [{'wikipedia_id': '447621', 'title': 'Las Vegas Strip', 'start_paragraph_id': 12, 'start_character': 0, 'end_paragraph_id': 12, 'end_character': 757, 'bleu_score': 0.9853469949554711, 'meta': {'yes_no_answer': 'NONE', 'annotation_id': 2508622776061719406}, 'section': 'Section::::History.:Early years (1930s–1990s).\n'}]}]