Consider $\mathrm{y}$-axis as internuclear axis. How many of the following will lead to $\mathrm{\pi }$ bond formation:

(i) ${\mathrm{p}}_{\mathrm{y}}-{\mathrm{p}}_{\mathrm{y}}$ (ii) ${\mathrm{p}}_{\mathrm{x}}-{\mathrm{p}}_{\mathrm{x}}$ (iii) ${\mathrm{p}}_{\mathrm{z}}-{\mathrm{p}}_{\mathrm{z}}$ (iv) ${\mathrm{d}}_{\mathrm{xy}}-{\mathrm{d}}_{\mathrm{xy}}$ (v) ${\mathrm{d}}_{\mathrm{yz}}-{\mathrm{d}}_{\mathrm{yz}}$ (vi) ${\mathrm{p}}_{\mathrm{x}}-{\mathrm{d}}_{\mathrm{xy}}$ (vii) ${\mathrm{d}}_{\mathrm{xy}}-{\mathrm{p}}_{\mathrm{z}}$ (viii) ${\mathrm{d}}_{\mathrm{xz}}-{\mathrm{d}}_{\mathrm{xz}}$

If the given compound is planar. Select the correct statement.

${\mathrm{N}}_2{\mathrm{O}}_4, {\left({\mathrm{HPO}}_3\right)}_3, {\mathrm{H}}_2{\mathrm{CO}}_3, {\mathrm{SO}}_2, {\mathrm{SO}}_3, {\mathrm{P}}_4{\mathrm{O}}_{10}{\mathrm{H}}_2{\mathrm{SO}}_4, {\mathrm{N}}_2{\mathrm{O}}_3, {\mathrm{HNO}}_3, {\mathrm{H}}_3{\mathrm{PO}}_3$
$\left(\mathrm{a}\right)$ Among the above compounds, compounds having at least one $\mathrm{p\pi }-\mathrm{p\pi }$ bond are $\mathrm{x}$
$\left(\mathrm{b}\right)$ Among the above compounds, compounds having at least one $\mathrm{d\pi }-\mathrm{p\pi }$ bond are $\mathrm{y}$
Give the answer as $\mathrm{x}+\mathrm{y}$.