Access to the Black Sea and gas pipelines to Europe. Without those pipelines, the Russian economy would tank in a minute and the country would collapse back to the bad old '90s.
They have plenty of access to the black sea. 3/4 of the east side of it is on their side.
The only decent port on Russian territory is Novorossiysk. That and Sevastopol are the the Russian Navy's only warm water ports.