You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
4-[2-ethylsulfanyl-3-[4-(1-hydroxy-3-methylbutan-2-yl)oxan-2-yl]propyl]piperidin-2-one is the IUPAC name of a molecule. Please give its molecular formula.
user
C20H37NO3S
assistant