8. As shown in Figure 1, an equilateral triangle $\triangle A N B$ with side length 1 is placed inside a rectangle $M N P Q$ with side lengths $M N=3, N P=4$, and $N B$ lies on side $N P$. If the equilateral triangle rolls around the inside of the rectangle along sides $N P, P Q, Q M$, and $M N$ and returns to its original starting position, then the total length of the path traced by vertex $A$ during the rolling process is $\qquad$ (保留 $\pi$ ).

保留 $\pi$) should be kept as (保留 $\pi$) or can be translated to (保留 $\pi$) as (保留 $\pi$) means "保留 $\pi$" in Chinese, which translates to "保留 $\pi$" in English. However, for clarity, it is better to use "保留 $\pi$" or "保留 $\pi$" in the context of the problem. For the final answer, I will use "保留 $\pi$":

If the total length of the path traced by vertex $A$ during the rolling process is $\qquad$ (保留 $\pi$).
$8.5 \pi$