You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
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3-methyl-2-(1,3-thiazol-4-ylmethyl)-3,6,7,8,9,9a-hexahydropyrido[1,2-a]pyrazine-1,4-dione is the IUPAC name of a molecule. Please give its molecular formula.
user
C13H17N3O2S
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