Let $$f : (0, \pi) \rightarrow \mathbb{R}$$ be a function given by
$$f(x) = \begin{cases} \left(\frac{8}{7}\right)^{\frac{\tan 8x}{\tan 7x}}, & 0 < x < \frac{\pi}{2} \\ a - 8, & x = \frac{\pi}{2} \\ (1 + |\cot x|)^{\frac{b}{|\tan x|}}, & \frac{\pi}{2} < x < \pi \end{cases}$$
where $$a, b \in \mathbb{Z}$$. If $$f$$ is continuous at $$x = \frac{\pi}{2}$$, then $$a^2 + b^2$$ is equal to ________