You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
Translate the chemical IUPAC name N-[(3aS,6aR)-3-benzyl-5,5-dioxo-3a,4,6,6a-tetrahydrothieno[3,4-d][1,3]thiazol-2-ylidene]-3,4-dimethoxybenzamide into its molecular formula.
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C21H22N2O5S2
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