You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
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4-[5-[(5-bromoindol-3-ylidene)methyl]-4-hydroxy-2-sulfanylidene-1,3-thiazol-3-yl]butanoic acid is the IUPAC name of a molecule. Please give its molecular formula.
user
C16H13BrN2O3S2
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