Which of these communist countries remained outside the warsaw pact? hungary east germany yugoslavia czechoslovakia?

Yugoslavia did not join the Warsaw Pact created in 1995 to counter the western pact--NATO. The Warsaw Pact included the USSR, Albania, Bulgaria, Hungary, Czechoslovakia, East Germany, Poland, and Romania. Yugoslavia was the only communist country not to join. They were essentially disowned by the communist block after refusing to recognize the USSR as the supreme communist power in 1948. 

The mountains on the east would be taller

Are their any multiple answer's ?