You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
5-chloro-N-[(3-chlorophenyl)methyl]spiro[1,4-dihydroquinoxaline-3,4'-oxane]-2-imine The above is the IUPAC name of a molecule. Write its molecular formula.
user
C19H19Cl2N3O
assistant