You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
Convert the IUPAC name of a molecule N-[(3aS,6aR)-3-[(1R,2R,4R)-2-bicyclo[2.2.1]heptanyl]-5,5-dioxo-3a,4,6,6a-tetrahydrothieno[3,4-d][1,3]thiazol-2-ylidene]-2-(4-methylphenyl)acetamide into molecular formula.
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C21H26N2O3S2
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