You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
(1-oxidopyridin-1-ium-4-yl)-[4-(4-propan-2-ylphenyl)sulfonylpiperazin-1-yl]methanone is the IUPAC name of a molecule. Please give its molecular formula.
user
C19H23N3O4S
assistant