A uniform flat disk of radius \(R\) has a circular hole of radius \(R/2\) removed from it, as shown in the figure. The center of the circular hole is located at a distance of \(R/2\) from the center \(O\) of the original disk. The remaining planar object has a total mass \(M\). In terms of \(M\) and \(R\), what is the rotational inertia of the remaining object about an axis perpendicular to the plane of the disk and passing through the original center \(O\)?