You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
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Under IUPAC nomenclature, a molecule named (5S)-7-(cyclobutylmethyl)-2-(5-methoxy-4-oxopyran-2-carbonyl)-2,7-diazaspiro[4.5]decan-6-one is given. What is its corresponding molecular formula?
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C20H26N2O5
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