You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
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Convert the IUPAC name of a molecule 1-[(5-methyl-1,2,4-oxadiazol-3-yl)methyl]-6-phenyl-3-piperidin-4-ylthieno[3,2-d]pyrimidine-2,4-dione into molecular formula.
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C21H21N5O3S
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