Aldehydes, Ketones and Carboxylic Acids

An organic compound P having molecular formula C6H6O3 gives ferric chloride test and does not have intramolecular hydrogen bond. The compound P reacts with 3 equivalents of NH2‌OH to produce oxime Q . Treatment ofP with excess methyl iodide in the presence of KOH produces compound R as the major product. Reaction of R with excess iso-butylmagnesium bromide followed by treatment with H3O+ gives compound S as the major product.
The total number of methyl (−CH3) group(s) in compound S is ________.