You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
3-[6-[[(2-aminocyclopentyl)methylamino]methyl]-3-oxo-1H-isoindol-2-yl]piperidine-2,6-dione The above is the IUPAC name of a molecule. Write its molecular formula.
user
C20H26N4O3
assistant