rotaional motion

Two balls of mass ${ m }_{ 1 }=56g$ and ${ m }_{ 2 }=28g$ are suspended on two threads of length ${ l }_{ 1 }=7cm$ and ${ l }_{ 2 }=11cm$ at the end of a freely hanging rod (see fig). Determine the angular velocity $w$ at which the rod should be rotated about the vertical axle so that it remains in vertical position![]

sorry for blurred image.

Give the answer in rad/s.

round off your answer.