Period of a two-m pendulum?

Given a two-m pendulum, that is, two mes attached to a rod (of negligible m) with the pivot point at the middle of the rod, what is the period of the pendulum when released from rest (with the rod horizontal) if one m is 200 g, the other is 100 g, and the length of the rod from the midpoint to each m is 20 cm (the rod is 40 cm long in all)?