Which of these countries exists?
Only one country from the list exists - the Republic of China, which is the official name of a sovereign state Taiwan.
This might be interesting: The German Democratic republic (or East Germany) was a part of Germany occupied by the Soviet Union. It was founded in 1949 and got back together with the rest of the country in 1990. Czechoslovakia split into Slovakia and the Czech Republic in 1993. Fortunately, it was a self-determined split and both sides separated in peace.