You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
Translate the chemical IUPAC name 3-[2-(3H-1,3-benzothiazol-2-ylidenemethyl)-3-(3-sulfopropyl)-1,3-benzothiazol-3-ium-4-yl]propane-1-sulfonic acid;hydroxide into its molecular formula.
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C21H24N2O7S4
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