You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
2-chloro-N-(5-cyclopropyl-1,3,4-thiadiazol-2-yl)-5-[phenyl(prop-2-enyl)sulfamoyl]benzamide is the IUPAC name of a molecule. Please give its molecular formula.
user
C21H19ClN4O3S2
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