You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
(1S,3R,3aR,6aS)-5-[(2R)-butan-2-yl]-5'-chloro-1-[(1S)-1-hydroxyethyl]spiro[1,2,3a,6a-tetrahydropyrrolo[3,4-c]pyrrole-3,3'-1H-indole]-2',4,6-trione The above is the IUPAC name of a molecule. Write its molecular formula.
user
C19H22ClN3O4
assistant