You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
For the molecule named 2-[1-[(2-methyl-1H-imidazol-5-yl)methyl]piperidin-4-yl]-3-(trifluoromethyl)benzaldehyde by IUPAC nomenclature, provide its molecular formula.
user
C18H20F3N3O
assistant