You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
Translate the chemical IUPAC name 4-[(2-oxo-3,4-dihydro-1H-quinolin-6-yl)oxy]-N-(5-phenyl-1,3,4-thiadiazol-2-yl)butanamide into its molecular formula.
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C21H20N4O3S
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