You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
8-methyl-5-(3-methyl-4-nitrophenyl)-6H-[1,3]dioxolo[4,5-h][1,2]benzodiazepine is the IUPAC name of a molecule. Please give its molecular formula.
user
C18H15N3O4
assistant