You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
N-(1,1-dioxothiolan-3-yl)-N-methyl-2-[methyl-[(2-piperidin-1-ylphenyl)methyl]amino]acetamide is the IUPAC name of a molecule. Please give its molecular formula.
user
C20H31N3O3S
assistant