You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
1-[7-(3-chlorophenyl)-9-hydroxy-3,5-dihydro-2H-1,4-benzoxazepin-4-yl]-2-methylsulfanylpropan-1-one is the IUPAC name of a molecule. Please give its molecular formula.
user
C19H20ClNO3S
assistant