Set up an integral in spherical coordinates to evaluate ${}_E\frac{4}{x^2+y^2+z^2}dV,$ where $E$ is the region bounded by the spheres $x^2+y^2+z^2=9$ and $x^2+y^2+z^2=36$ in the octant given by and $z>0.$

Choose values from the domains: $0,02,$ and $0.$ Enter rho to denote $,$ theta to denote $,$ phi to denote $,$ and pi to denote $.$

Complete the integration to compute the volume. Enter an exact answer.