Question: who fought at the battles of tannenburg and masurian lakes
[{'answer': 'Russia', 'provenance': [{'wikipedia_id': '60142', 'title': 'Battle of Tannenberg', 'start_paragraph_id': 1, 'start_character': 44, 'end_paragraph_id': 1, 'end_character': 50, 'bleu_score': 1.0, 'section': 'Section::::Abstract.'}]}, {'answer': 'Germany', 'provenance': [{'wikipedia_id': '60142', 'title': 'Battle of Tannenberg', 'start_paragraph_id': 1, 'start_character': 55, 'end_paragraph_id': 1, 'end_character': 62, 'bleu_score': 1.0, 'section': 'Section::::Abstract.'}]}, {'provenance': [{'wikipedia_id': '60142', 'title': 'Battle of Tannenberg', 'start_paragraph_id': 1, 'start_character': 0, 'end_paragraph_id': 1, 'end_character': 771, 'bleu_score': 0.9577362712813341, 'meta': {'yes_no_answer': 'NONE', 'annotation_id': 4976964865172373623}, 'section': 'Section::::Abstract.'}]}]