Question: where was kievan rus and why is it named that
[{'answer': 'Europe', 'provenance': [{'wikipedia_id': '21486360', 'title': "Kievan Rus'", 'start_paragraph_id': 1, 'start_character': 84, 'end_paragraph_id': 1, 'end_character': 90, 'bleu_score': 1.0, 'section': 'Section::::Abstract.'}]}, {'answer': "peoples of Belarus , Ukraine and Russia all claim Kievan Rus ' as their cultural ancestors , with Belarus and Russia deriving their names from it"}]