Question 86
In a circle $O$, there are six points, $A, B, C, D, E, F$ in a counterclockwise order. $BD \perp CF$, and $CF, BE, AD$ are concurrent. Let the perpendicular from $B$ to $AC$ be $M$, and the perpendicular from $D$ to $CE$ be $N$. Prove that $AE \parallel MN$.