You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
3-(4-hydroxyphenyl)-1-[4-(1H-imidazol-2-ylmethyl)piperidin-1-yl]-2,2-dimethylpropan-1-one is the IUPAC name of a molecule. Please give its molecular formula.
user
C20H27N3O2
assistant