You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
(2S)-1'-[(2,6-dichlorophenyl)methyl]-3-(3-methylphenyl)spiro[1H-quinazoline-2,3'-indole]-2',4-dione The above is the IUPAC name of a molecule. Write its molecular formula.
user
C29H21Cl2N3O2
assistant