You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
3-[[3-chloro-5-(2-chloro-4-ethylsulfonylphenoxy)phenyl]methyl]-2,5-dihydro-1,2,4-oxadiazole The above is the IUPAC name of a molecule. Write its molecular formula.
user
C17H16Cl2N2O4S
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