You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
(1S,3aR,6aS)-1-(2,4-dichlorophenyl)-5-(4-methylphenyl)spiro[3a,6a-dihydro-1H-furo[3,4-c]pyrrole-3,2'-indene]-1',3',4,6-tetrone The above is the IUPAC name of a molecule. Write its molecular formula.
user
C27H17Cl2NO5
assistant