You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
2-amino-N-oxo-3-[3-[(4-oxo-3H-quinazolin-2-yl)sulfanylmethyl]phenyl]propanamide is the IUPAC name of a molecule. Please give its molecular formula.
user
C18H16N4O3S
assistant