Question: when did the vietnam war start for us
[{'answer': '1965', 'provenance': [{'wikipedia_id': '32611', 'title': 'Vietnam War', 'start_paragraph_id': 64, 'start_character': 164, 'end_paragraph_id': 64, 'end_character': 168, 'bleu_score': 1.0, 'section': "Section::::Johnson's escalation, 1963–69.:Gulf of Tonkin incident.\n"}]}]