$2 \mathrm{NO}(\mathrm{g})+\mathrm{Cl}_2(\mathrm{~g}) \rightleftharpoons 2 \mathrm{NOCl}(\mathrm{s})$
This reaction was studied at $-10^{\circ} \mathrm{C}$ and the following data was obtained

$[\mathrm{NO}]_0$ and $\left[\mathrm{Cl}_2\right]_0$ are the initial concentrations and $\mathrm{r}_0$ is the initial reaction rate.
The overall order of the reaction is $\_\_\_\_$
(Round of to the Nearest Integer).