Find the missing exponent of the simplified expression.

$\displaystyle{{\left(\frac{{{4}{{g}}^{{6}}{{h}}^{{2}}}}{{{{f{{g}}}}^{{2}}}}\right)}}^{{4}}=\frac{{{256}{{g}}^{?}{{h}}^{{8}}}}{{{{f}}^{{4}}}}\usepackage{cmbright}\Huge\$