You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
(3aS,5R,7aS)-2-(2,4-dimethylphenyl)-5-phenyl-3a,4,5,6,7,7a-hexahydroisoindole-1,3-dione is the IUPAC name of a molecule. Please give its molecular formula.
user
C22H23NO2
assistant