You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
Under IUPAC nomenclature, a molecule named N-[2-[4-(4-bromophenyl)butan-2-ylamino]-2-oxoethyl]-3,4-dimethoxybenzamide is given. What is its corresponding molecular formula?
user
C21H25BrN2O4
assistant