The number of Geometrical Isomers of $\left[\mathrm{Co}{\left({\mathrm{NH}}_3\right)}_3{\left({\mathrm{NO}}_3\right)}_3\right]$ is __.

$\left[\mathrm{Co}{\left({\mathrm{NH}}_3\right)}_3{\left({\mathrm{NO}}_3\right)}_3\right]$ has two geometrical isomers, cis or fac or facial isomer and trans or mer or meridional isomer.