You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
(3S)-N-[(2,4-dichlorophenyl)methyl]-1-(2,5-dichlorophenyl)sulfonylpiperidine-3-carboxamide The above is the IUPAC name of a molecule. Write its molecular formula.
user
C19H18Cl4N2O3S
assistant