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 [3-(4-fluorophenyl)-1H-pyrazol-5-yl]-[4-[3-(trifluoromethyl)phenyl]piperazin-1-yl]methanone is given. What is its corresponding molecular formula?
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C21H18F4N4O
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