A hydroxy compound (\( X \)) with molar mass \( 122 \, \mathrm{g \, mol^{-1}} \) is acetylated with acetic anhydride, using a large excess of the reagent ensuring complete acetylation of all hydroxyl groups. The product obtained has a molar mass of \( 290 \, \mathrm{g \, mol^{-1}} \). The number of hydroxyl groups present in compound (\( X \)) is: