If $g$ has finite order $n$ show that $n$ is the least number such that $g^n$ is the neutral element

If $g$ has finite order $n$ show that $n$ is the least number such that
$g^n$ is the neutral element

pThe order of the element $g$ is the size (cardinality) of the group
$\langle g \rangle$. If $g$ has finite order $n$ show that $n$ is the
least number such that $g^n$ is the neutral element./p