You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
Under IUPAC nomenclature, a molecule named [(3S)-1-[1-(7H-purin-6-yl)piperidin-4-yl]piperidin-3-yl]-pyrrolidin-1-ylmethanone is given. What is its corresponding molecular formula?
user
C20H29N7O
assistant