Mertens Equations

The Mertens function is the summatory function of the Möbius function.

$M(n)=\sum _{k\le n}\mu (k)$

Find the first i such as $M(i)=-9876$ and the first j such as $M(j)=+9876$

Answer format: i,j

You are given: $12855874,10193871$ // For $\pm 1234$

[My timing: 60 sec]