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 (5E)-3-(1,1-dioxothiolan-3-yl)-5-[[2-(ethylamino)-9-methyl-4-oxopyrido[1,2-a]pyrimidin-3-yl]methylidene]-2-sulfanylidene-1,3-thiazolidin-4-one into molecular formula.
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C19H20N4O4S3
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