You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
(3aR,4S,8aS,8bS)-2-(2-methylphenyl)spiro[3a,6,7,8,8a,8b-hexahydropyrrolo[3,4-a]pyrrolizine-4,6'-indolo[2,1-b]quinazoline]-1,3,12'-trione The above is the IUPAC name of a molecule. Write its molecular formula.
user
C30H24N4O3
assistant