The hard part is dealing with a scenario where there is plenty of wheat, but people have no money to buy it.
Ireland, in the 1840s suffered a horrific famine. Grain was being exported the while time. Food existed. People couldn't afford it.
During the US' great depression, people were hungry while agricultural products piled up, rotted in or burned to defend a price floor.
I don't think Russia will starve, but economics is hard. There are a lot of ways this can get really bad.