Question: who was involved in the battle of okinawa
[{'answer': 'United States', 'provenance': [{'wikipedia_id': '4986', 'title': 'Battle of Okinawa', 'start_paragraph_id': 1, 'start_character': 110, 'end_paragraph_id': 1, 'end_character': 123, 'bleu_score': 1.0, 'section': 'Section::::Abstract.'}]}, {'answer': 'United Kingdom', 'provenance': [{'wikipedia_id': '4986', 'title': 'Battle of Okinawa', 'start_paragraph_id': 56, 'start_character': 481, 'end_paragraph_id': 56, 'end_character': 495, 'bleu_score': 1.0, 'section': 'Section::::Casualties.\n'}]}, {'answer': 'Canada'}, {'answer': 'New Zealand', 'provenance': [{'wikipedia_id': '4986', 'title': 'Battle of Okinawa', 'start_paragraph_id': 9, 'start_character': 142, 'end_paragraph_id': 9, 'end_character': 153, 'bleu_score': 1.0, 'section': 'Section::::Order of battle.:Allied.\n'}]}, {'answer': 'Australia', 'provenance': [{'wikipedia_id': '4986', 'title': 'Battle of Okinawa', 'start_paragraph_id': 9, 'start_character': 130, 'end_paragraph_id': 9, 'end_character': 139, 'bleu_score': 1.0, 'section': 'Section::::Order of battle.:Allied.\n'}]}, {'answer': 'Japan', 'provenance': [{'wikipedia_id': '4986', 'title': 'Battle of Okinawa', 'start_paragraph_id': 1, 'start_character': 168, 'end_paragraph_id': 1, 'end_character': 173, 'bleu_score': 1.0, 'section': 'Section::::Abstract.'}]}]