Question: when did the ussr agree to a unified germany inside of nato
[{'answer': 'May 1990', 'provenance': [{'wikipedia_id': '61103', 'title': 'German reunification', 'start_paragraph_id': 17, 'start_character': 84, 'end_paragraph_id': 17, 'end_character': 92, 'bleu_score': 1.0, 'section': 'Section::::Process of reunification.:Economic merger.\n'}]}, {'provenance': [{'wikipedia_id': '61103', 'title': 'German reunification', 'start_paragraph_id': 47, 'start_character': 0, 'end_paragraph_id': 47, 'end_character': 672, 'bleu_score': 0.981898582188057, 'meta': {'yes_no_answer': 'NONE', 'annotation_id': 16205654971087100152}, 'section': 'Section::::Foreign support and opposition.:Four powers.\n'}]}]