You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
4-fluoro-2-methyl-N-(5-methyl-6-oxobenzo[b][1,4]benzoxazepin-8-yl)benzenesulfonamide The above is the IUPAC name of a molecule. Write its molecular formula.
user
C21H17FN2O4S
assistant