You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
9-bromo-8-methoxy-2-methyl-6-(4-nitrophenyl)-11H-imidazo[1,2-c][2,3]benzodiazepine The above is the IUPAC name of a molecule. Write its molecular formula.
user
C19H15BrN4O3
assistant