You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
2-[(3-bromophenyl)methyl-[2-(3,5-dichloro-N-methylsulfonylanilino)acetyl]amino]-N-ethylpropanamide The above is the IUPAC name of a molecule. Write its molecular formula.
user
C21H24BrCl2N3O4S
assistant