You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
2-[1-[2-(1-methylindol-3-yl)acetyl]azetidin-3-yl]-3a,4,7,7a-tetrahydroisoindole-1,3-dione The above is the IUPAC name of a molecule. Write its molecular formula.
user
C22H23N3O3
assistant