Sum Of Squared Reciprocals - Mobius Function

Number Theory Level 3

$\sum_{\mu(n)=1} \frac{1}{n^2} = \frac{A}{B\pi^C}$

Let $\mu(n)$ denote the möbius function, the sum is taken over all positive integers $n$ such that $\mu(n)=1$ , with coprime positive integers $A$ and $B.$ Find $A+B+C$ .