[muyuu]

Funnily, the UN takes a stereotyped approach to this classification rather than geographical one:

https://en.wikipedia.org/wiki/Eastern_Europe#UN

There, Slovakia is classified as Eastern, East-Central more concretely.

The westernmost countries of Europe, Spain and Portugal, are not classified as Western by the UN. The CIA considers them Western Europe though, and Slovakia is Central Europe for them.

I have to say that the CIA classification makes a lot more sense to me, the UN one seems to take a perceived cultural/economic approach that's both fuzzy and stereotyped.