In a triangle $ABC$, let $AA', BB'$ and $CC'$ be the bisectors. Suppose $A'B' \cap CC' =P$ and $A'C' \cap BB'= Q$. Prove that $\angle PAC = \angle QAB$.
Problem
Source: 2007 Sharygin Geometry Olympiad Correspondence Round P15
Tags: geometry, equal angles, Angle Bisectors