You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
5-[(1,1-dioxothiolan-3-yl)-methylamino]-N-ethyl-N-(3-methylphenyl)pyridine-3-carboxamide is the IUPAC name of a molecule. Please give its molecular formula.
user
C20H25N3O3S
assistant