A certain gas obeys $\mathrm{P}\left(\mathrm{V}_{\mathrm{m}}-\mathrm{b}\right)=\mathrm{RT}$. The value of $\left(\frac{\partial \mathrm{Z}}{\partial \mathrm{P}}\right)_{\mathrm{T}}$ is $\frac{\mathrm{xb}}{\mathrm{RT}}$. The value of x is $\_\_\_\_$ .
(Integer answer) (Z: compressibility factor)
