You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
(1R,3R,3aR,6aR)-5-(1,3-benzodioxol-5-ylmethyl)-5'-chloro-1-[(4-hydroxyphenyl)methyl]spiro[1,2,3a,6a-tetrahydropyrrolo[3,4-c]pyrrole-3,3'-1H-indole]-2',4,6-trione is the IUPAC name of a molecule. Please give its molecular formula.
user
C28H22ClN3O6
assistant