62. On a plane, there are two lines intersecting at point $O$, and two points $A$ and $B$. Denote the bases of the perpendiculars dropped from $A$ to the given lines as $M$ and $N$, and the bases of the perpendiculars dropped from $B$ as $K$ and $L$. Find the angle between the lines $M N$ and $K L$, if $\widehat{A O B}=\alpha \leqslant 90^{\circ}$.