5. In an equilateral triangle $ABC$ with side length $a$, points $M, N, P, Q$ are positioned as shown in the figure. It is known that $MA + AN = PC + CQ = a$. Find the measure of angle $NOQ$.

![](https://cdn.mathpix.com/cropped/2024_05_06_09b0e7336bad4773d41eg-3.jpg?height=397&width=462&top_left_y=2114&top_left_x=837)