An organic compound \(\mathbf{P}\) having molecular formula \({\mathrm{C}}_{6}{\mathrm{H}}_{6}{\mathrm{O}}_{3}\) gives f…

An organic compound \(\mathbf{P}\) having molecular formula \({\mathrm{C}}_{6}{\mathrm{H}}_{6}{\mathrm{O}}_{3}\) gives ferric chloride test and does not have intramolecular hydrogen bond. The compound \(\mathbf{P}\) reacts with 3 equivalents of \({\mathrm{NH}}_{2}\mathrm{OH}\) to produce oxime Q. Treatment of \(\mathbf{P}\) with excess methyl iodide in the presence of \(\mathrm{KOH}\) produces compound \(\mathbf{R}\) as the major product. Reaction of \(\mathbf{R}\) with excess iso-butylmagnesium bromide followed by treatment with \({\mathrm{H}}_{3}{\mathrm{O}}^{+}\)gives compound \(S\) as the major product.

The total number of methyl \(\left(-{\mathrm{CH}}_{3}\right)\) group(s) in compound \(S\) is _____ .