As ever with projects like this, it’s quite tricky to define the scope, particularly what we class as a country. Here we’re going to take the simplest, and generally narrowest, definition: every UN Member State. This is certainly a contentious definition, and there are quite a few high profile omissions from this. But that’s the scope we’re working with.
In Wikidata terms that’s quite a simple list to generate:
https://gist.github.com/tmtmtmtm/62c0c4ae36a58fbc666f5be9de8549a3
This gives us the 193 members we expect.