Given triangle $ ABC$ and $ AB=c$, $ AC=b$ and $ BC=a$ satisfying $ a \geq b \geq c$, $ BE$ and $ CF$ are two interior angle bisectors. $ P$ is a point inside triangle $ AEF$. $ R$ and $ Q$ are the projections of $ P$ on sides $ AB$ and $ AC$. Prove that $ PR + PQ + RQ < b$.