You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
Translate the chemical IUPAC name 4-(3,4-difluoro-N-methylsulfonylanilino)-N-[5-(4-methylphenyl)-1,3,4-thiadiazol-2-yl]butanamide into its molecular formula.
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C20H20F2N4O3S2
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