You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
1-methyl-4-[1-[4-nitro-2-(2,2,2-trifluoroethoxy)phenyl]piperidin-4-yl]piperazine The above is the IUPAC name of a molecule. Write its molecular formula.
user
C18H25F3N4O3
assistant