You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
N-[2-(cyclohexen-1-yl)ethyl]-2-[5-methoxy-4-oxo-2-(thiomorpholin-4-ylmethyl)pyridin-1-yl]acetamide is the IUPAC name of a molecule. Please give its molecular formula.
user
C21H31N3O3S
assistant