Question: which president was the first to send military advisers to south vietnam
[{'answer': 'Truman', 'provenance': [{'wikipedia_id': '8453309', 'title': 'Role of the United States in the Vietnam War', 'start_paragraph_id': 1, 'start_character': 428, 'end_paragraph_id': 1, 'end_character': 434, 'bleu_score': 1.0, 'section': 'Section::::Abstract.'}]}, {'provenance': [{'wikipedia_id': '8453309', 'title': 'Role of the United States in the Vietnam War', 'start_paragraph_id': 19, 'start_character': 0, 'end_paragraph_id': 19, 'end_character': 330, 'bleu_score': 0.962600167205617, 'meta': {'yes_no_answer': 'NONE', 'annotation_id': 8978804871726424814}, 'section': 'Section::::Timeline.:Harry S. Truman (1945–53).\n'}]}]