Question: what type of government is the us system
[{'answer': 'Republic', 'provenance': [{'wikipedia_id': '325218', 'title': 'List of countries by system of government', 'start_paragraph_id': 4, 'start_character': 66, 'end_paragraph_id': 4, 'end_character': 74, 'bleu_score': 1.0, 'section': 'Section::::List of countries.:UN member states and observers.\n'}]}]