10 Let $x, y, z \in \mathbf{R}^{+}$, and satisfy $x y z + x + z = y$, find the maximum value of $p = \frac{2}{x^{2}+1} - \frac{2}{y^{2}+1} + \frac{3}{z^{2}+1}$.
\begin{array}{l}\text { 10. Given, } x+(-y)+z=x \cdot(-y) \cdot z \text {. } \\ \text { Let } x=\tan \alpha, y=-\tan \beta, z=\tan \gamma,(\alpha+\beta+\gamma=k \pi) . \\ \text { Therefore, } p=2 \cos ^{2} \alpha-2 \cos ^{2} \beta+3 \cos ^{2} \gamma=2 \cos ^{2} \alpha-2 \cos ^{2} \beta+3 \cos ^{2}(\alpha+\beta)= \\ -2 \sin (\alpha+\beta) \sin (\alpha-\beta)+3 \cos ^{2} \gamma \leqslant 2 \sin \gamma+3-3 \sin ^{2} \gamma=-3\left(\sin \gamma-\frac{1}{3}\right)^{2}+ \\ \frac{10}{3} \leqslant \frac{10}{3} \text {, hence } p_{\max }=\frac{10}{3} .\end{array}