Scary Limit

Calculus Level 4

$\large \lim_{x\rightarrow 0} \left\{\sin^{2}\left(\dfrac{\pi}{2-ax}\right)\right\}^{\sec^{2}\left(\frac{\pi}{2-bx}\right)}$

If the value of the above limit is in the form $e^{k\left(\frac{a^2}{b^2}\right)}$ , where $k$ is a integer, then find $-2017k$ .