You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
N-[3-[[5-(4-bromophenyl)-1,3,4-thiadiazol-2-yl]amino]-3-oxopropyl]-3-fluoro-N-(2-methoxyethyl)benzamide The above is the IUPAC name of a molecule. Write its molecular formula.
user
C21H20BrFN4O3S
assistant