Question: Samvel Alumyan was a Soviet-Armenian classical pianist and frequent collaborator with a violinist many considered to be among the greatest violinists of what?
{'answer': 'the 20th century', 'supporting_facts': [['Samvel Alumyan', 0], ['Samvel Alumyan', 2], ['Leonid Kogan', 0], ['Leonid Kogan', 1]]}