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 (7Z)-7-[(4-ethoxyphenyl)methylidene]-3-(4-methylphenyl)-2,4-dihydro-[1,3]thiazolo[3,2-a][1,3,5]triazin-6-one is given. What is its corresponding molecular formula?
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C21H21N3O2S
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