You can use one of Python morphology analyzers for Russian to normalize the word:
- https://github.com/kmike/pymorphy2
- https://github.com/kmike/pymorphy
- https://github.com/irokez/Pyrus
There is also a Porter stemmer for Russian in https://github.com/nltk/nltk. Also, you could employ http://company.yandex.ru/technologies/mystem/ from a command line.
I'd recommend pymorphy2 for your task, but I'm a bit biased :)