You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
(3-butyl-7-ethyl-2,6-dioxopurin-8-yl)methyl (2S)-1-(furan-2-carbonyl)pyrrolidine-2-carboxylate is the IUPAC name of a molecule. Please give its molecular formula.
user
C22H27N5O6
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