You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
Convert the IUPAC name of a molecule (2R)-2-[3-[(2S)-butan-2-yl]-4-oxoquinazolin-2-yl]sulfanyl-N-(4-ethylphenyl)propanamide into molecular formula.
user
C23H27N3O2S
assistant