You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
For the molecule named [2-methyl-3-(5-propan-2-yl-1,2,4-oxadiazol-3-yl)-2,8-diazaspiro[4.5]decan-8-yl]-(5-methylthiophen-2-yl)methanone by IUPAC nomenclature, provide its molecular formula.
user
C20H28N4O2S
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