The following mechanism has been proposed for the reaction of $NO$ with $B{r}_2$ to form $NOBr$

${\mathrm{NO}}_{\left(\mathrm{g}\right)}+{\mathrm{Br}}_{2\left(\mathrm{g}\right)}\rightleftharpoons {\mathrm{NOBr}}_{2\left(\mathrm{g}\right)}$

${\mathrm{NOBr}}_{2\left(\mathrm{g}\right)}+{\mathrm{NO}}_{\left(\mathrm{g}\right)}\to 2{\mathrm{NOBr}}_{\left(\mathrm{g}\right)}$

If the second step is rate determining step, then the Order of reaction with respect to $N{O}_{\left(g\right)}$ is