Solution
= Solution
Let $|G|=p^am$ with $p\nmid m$. The <Sylow theorems> state:
* $G$ has a <subgroup> of order $p^a$;
* every $p$-subgroup of $G$ is contained in a Sylow $p$-subgroup;
* all Sylow $p$-subgroups are conjugate;
* their number $n_p$ satisfies $n_p\equiv1\pmod p$ and $n_p\mid m$.