You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
Please write the molecular formula of the molecule propyl 2-[[(4R)-5-cyano-4-(4-ethylphenyl)-2-oxo-3,4-dihydro-1H-pyridin-6-yl]sulfanyl]acetate .
user
C19H22N2O3S
assistant