You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
Translate the chemical IUPAC name 1-[(S)-(3-chloro-4-fluorophenyl)-(4-methylsulfonylphenyl)methyl]-2-oxoimidazolidine-4-carboxamide into its molecular formula.
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C18H17ClFN3O4S
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