You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
(2S)-2-[7-(3-chlorophenyl)-9-hydroxy-3,5-dihydro-2H-1,4-benzoxazepin-4-yl]propanamide The above is the IUPAC name of a molecule. Write its molecular formula.
user
C18H19ClN2O3
assistant