There just simply aren't 250 countries.
(At the time of posting, parent was below zero)
If the definition Wolfram cared to use was "Passport issuing state recognised by other passport issuing states" then we might agree.
http://en.wikipedia.org/wiki/List_of_country_calling_codes has 275 in their complete listing; but then, quite a few aren't "countries"
The UK is a single state, but comprised of at least three countries. England, Wales, Scotland. Northern Ireland would not count as a 'country' I guess, though Ireland itself obviously is.