You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
Translate the chemical IUPAC name N-[2-(3-methylphenoxy)ethyl]-2-(4-oxo-5-thiophen-2-ylthieno[2,3-d]pyrimidin-3-yl)acetamide into its molecular formula.
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C21H19N3O3S2
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