Planetary Gear

How many independent inputs does a planetary gearset have? What about outputs?

Hint
A simple planetary gearset has a “sun” gear, an “arm” that rotates around the sun gear axis, one or more “planet” gears that rotate about about a point on the “arm”, and a “ring” gear (internal teeth) that is concentric with the “sun” gear.
Hint 2
A simple planetary gearset has a “sun” gear, an “arm” that rotates around the sun gear axis, one or more “planet” gears that rotate about about a point on the “arm”, and a “ring” gear (internal teeth) that is concentric with the “sun” gear. On one end, the “planet” gear(s) interlock with the “sun” gear, while simultaneously meshing with the “ring” gear on the other side. As a result, a planetary gearset has one output and two independent inputs.
Two independent inputs and one output