You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
Translate the chemical IUPAC name N-[(4-cyanophenyl)methyl]-2-(5,6-dimethylthieno[2,3-d]pyrimidin-4-yl)sulfanyl-N-prop-2-enylacetamide into its molecular formula.
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C21H20N4OS2
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