You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
5-[(3-nitrophenyl)methyl]-1,2,3,3a,10,10a-hexahydrocyclopenta[b][1,5]benzodiazepin-4-one The above is the IUPAC name of a molecule. Write its molecular formula.
user
C19H19N3O3
assistant