You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
For the molecule named 7-[(1R,2R,3R,5R)-3,5-dihydroxy-2-[(3S)-3-hydroxyoctyl]cyclopentyl]hept-2-enoic acid by IUPAC nomenclature, provide its molecular formula.
user
C20H36O5
assistant