Question: What is the name of this series of mass executions during World War II, which, along with Sambor Ghetto, was anenexed to the Ukranian SSR?
{'answer': 'NKVD prisoner massacres', 'supporting_facts': [['Sambor Ghetto', 0], ['Sambor Ghetto', 4], ['NKVD prisoner massacres', 0]]}