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 1-[4-(1-methylsulfanylpropan-2-yl)-1-oxa-4,9-diazaspiro[5.5]undecan-9-yl]-4-(1,2,4-triazol-1-yl)butan-1-one is given. What is its corresponding molecular formula?
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C18H31N5O2S
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