**kg** rigid rod with length $L$ is hinged at one end to the floor, so it can freely rotate in a certain plane perpendicular to the floor. A spring ($k=450$ **N/m**), which stretches in the same plane, is attached to the free end of the rod as well as a nearby wall. When the rod is straight up (perpendicular to the floor), the spring is not stretched and is perpendicular to the rod. If the rod is rotated very slightly (such that the effects of gravity are negligible) and released, what is its period of oscillation in **ms** (rounded to the nearest integer)?