You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
N-(1,3-benzothiazol-2-ylmethyl)-N-methyl-4,10-dioxo-5H-pyrrolo[1,2-b][1,2,5]benzothiadiazepine-7-carboxamide The above is the IUPAC name of a molecule. Write its molecular formula.
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C21H16N4O3S2
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