This bargain allowed the oligarchs to maintain their powers, in exchange for their explicit support of – and alignment with – Putin's government.[23][24] Many more business people have become oligarchs during Putin's time in power, and often due to personal relations with Putin, such as the rector of the institute where Putin obtained a degree in 1996, Vladimir Litvinenko,[25] and Putin's childhood friend and judo-teacher Arkady Rotenberg.[26] However, other analysts argue that the oligarchic structure has remained intact under Putin, with Putin devoting much of his time to mediating power-disputes between rival oligarchs.[5] Some had been imprisoned, such as Mikhael Mirilashvili.