There are a few different definitions of this (not all countries are recognised by the UN as being countries!). There are 193 states that are members of the UN (had to look that one up), as well as 13 states that are not members. There are lots of reasons why a state might not be a member of the UN! Sometimes the UN refuses to recognise the state as a country, while other times there is a question over who owns a piece of territory. It’s pretty complicated stuff!