A person standing at point $P$ sees angle of elevation of the top of a building, whose base is $50$ meters away, to be ${60}^{\mathrm{o}}$. Another building whose base is $20$ meters away from the base of the first building and is between the observer and first building has height $h$ meters, then the maximum possible height (in meters) of this second building is (Take $\sqrt{3}=1.73$)