You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
[4-[3-chloro-5-(trifluoromethyl)pyridin-2-yl]-1,4-diazepan-1-yl]-(4-ethoxy-3-methoxyphenyl)methanone The above is the IUPAC name of a molecule. Write its molecular formula.
user
C21H23ClF3N3O3
assistant