Newly independent South Sudan became the 193rd member of the United Nations this week, so that's another country to add onto the numbers in Boxtops' link.
As Jno indicates, the definition of a 'country' isn't as clear cut as it might at first seem. Should the United Kingdom be counted as one country, or as four?. What about the Channel Islands? All six of them are self-governing, so perhaps some people would say that they're all 'countries'? They're definitely not part of the UK but are they really 'separate'? (Don't even mention the Isle of Man!)
If there are that many confusion just around our own shores, it's easy to see how many more there might be throughout the rest of the world!
Chris