You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
Convert the IUPAC name of a molecule 6-[2-(4-hydroxy-4-thiophen-2-ylpiperidin-1-yl)acetyl]-3,4-dihydro-1H-quinolin-2-one into molecular formula.
user
C20H22N2O3S
assistant