Help with calculating the net torque acting on the lever?

A uniform horizontal lever of length 2.8 m is pivoted at its mid-point. The following forces are acting on the lever: a 7 N vertically upward force acting at the right end of the lever, a 3 N vertically downward froce acting at the left end of the lever, and a 9 N vertically downward force acting at a point on the lever 0.5 m away form the right end. Calculate the net torque acting on the lever.