NASA's Ames Research Center has a large centrifuge used for astronaut training. The centrifuge consists of a 3880-kg, 18.0-m-long tubular structure, which rotates about its center. Find the centrifuge's rotational inertia when two 105-kg seats are mounted at either end of the tube, 7.92 m from the rotation axis, and both are occupied by 72.6-kg astronauts. Treat the tube as a thin rod and the astronauts and seats as point masses.