Why does Russia need a navy?

Why does Russia even bother having a navy?

A navy creates defensive depth beyond Russia's coastline. The difficulty is funding enough sea power while the army takes priority along extensive land borders.

Russia's fear of invasion extends to its long coastlines. Leaving them undefended would allow an opponent to approach by sea without encountering resistance farther out. The army still receives priority because an invasion across a land frontier is easier to mount than one across the sea. Naval planners therefore have to secure maritime approaches with a smaller share of resources, within the limits of the national economy.