You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
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For the molecule named (2E)-8a-methyl-2-[[4-(trifluoromethyl)phenyl]methylidene]-4,4a,5,6,7,8-hexahydro-3H-naphthalen-1-one by IUPAC nomenclature, provide its molecular formula.
user
C19H21F3O
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