You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
2-[(2,4-dichlorophenyl)methylsulfanyl]-N-[1-[2-(methanesulfonamido)phenyl]ethyl]acetamide The above is the IUPAC name of a molecule. Write its molecular formula.
user
C18H20Cl2N2O3S2
assistant