Finland managed to inflict in between 230,000 and 270,000 fatalities plus 200,000-300,000 injuries on Russia,
For anyone who hasn’t read about the devastation visited on Russia’s army in the 1939 Finnish Winter War, here is great synopsis of how tough and smart the Finns are:
http://www.historyhouse.com/in_history/winter_war/
During the Winter War, they had a kill ratio of 218-47 (plus 30 captured after being forced to land). During the Continuation War (1941-44) they had a ratio of 1,621-210. Then, following the end of hostilities with the Soviet Union, the Finns fought the Nazis in the Lapland War, where they scored the only 3 aerial victories of this conflict.
Flying the obsolete US F2 Brewster B239 "Buffalo", the Finns had a 459-15 kill ratio!