Question: who was the last president to go to south korea
[{'answer': 'Donald Trump', 'provenance': [{'wikipedia_id': '51161081', 'title': 'United States presidential visits to East Asia', 'start_paragraph_id': 2, 'start_character': 156, 'end_paragraph_id': 2, 'end_character': 168, 'bleu_score': 1.0, 'section': 'Section::::Abstract.'}]}]