You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
Please write the molecular formula of the molecule 3-[4-chloro-3-(trifluoromethyl)phenyl]-5-(4-nitrophenyl)-2-(trifluoromethyl)-2,3,3a,4-tetrahydro-1H-pyrazolo[1,5-a]pyrimidin-7-one .
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C20H13ClF6N4O3
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