You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
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Translate the chemical IUPAC name (5Z)-5-[(4-butoxyphenyl)methylidene]-1-(4-chlorophenyl)-2-sulfanylidene-1,3-diazinane-4,6-dione into its molecular formula.
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C21H19ClN2O3S
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