You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
9-(3-chloro-2-methylphenyl)sulfonyl-3-cyclohexyl-1-oxa-2,9-diazaspiro[4.5]dec-3-ene is the IUPAC name of a molecule. Please give its molecular formula.
user
C20H27ClN2O3S
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