You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
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Under IUPAC nomenclature, a molecule named 1-[3-[(5-phenylthieno[2,3-d]pyrimidin-4-yl)amino]propanoyl]piperidine-4-carboxamide is given. What is its corresponding molecular formula?
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C21H23N5O2S
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