All 4. First you have to get the plane pointed up. Then you have to modulate the throttle so it stops going up and make sure it doesn't come down. Then you have to work the elevator and rudder to keep the tail underneath the engine. Once you get the tail in the "sweet spot" it sorta locks in. You can either let the plane torque itself around or use opposite (right) aileron to keep the top pointed at you (a good thing when you're just learning).

GOod luck!