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 2-[[5-oxo-2-(2-oxo-2-piperidin-1-ylethyl)-[1,3,4]thiadiazolo[3,2-a]pyrimidin-7-yl]methylsulfanyl]acetic acid into molecular formula.
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C15H18N4O4S2
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