Paragraph:
A carbonyl compound $P$, which gives positive iodoform test, undergoes reaction with MeMgBr followed by dehydration to give an olefin $Q$. Ozonolysis of $Q$ leads to a dicarbonyl compound $R$, which undergoes intramolecular aldol reaction to give predominantly $S$.

$$
P \underset{\text { (ii) } \mathrm{H}^{+}, \mathrm{H}_2 \mathrm{O}}{\stackrel{\text { (i) } \mathrm{MeMgBr}}{\longrightarrow}} \mathrm{Q} \underset{\text { Heat }}{\stackrel{\mathrm{O}_3 / \mathrm{Zn}-\mathrm{H}_2 \mathrm{O}}{\longrightarrow}} \mathrm{P}
$$
(iii) $\mathrm{H}_2 \mathrm{SO}_4$ /HeatQuestion:
$$
\text { The structures of the products } Q \text { and } R \text {, respectively, are }
$$