You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
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For the molecule named 5-nitro-6-(4-phenylpiperazin-1-yl)-N-[4-(trifluoromethoxy)phenyl]pyrimidin-4-amine by IUPAC nomenclature, provide its molecular formula.
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C21H19F3N6O3
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