You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
7-chloro-5-nitro-6-(trifluoromethyl)-1,4-dihydroquinoxaline-2,3-dione;6-chloro-7-(trifluoromethyl)-1,4-dihydroquinoxaline-2,3-dione is the IUPAC name of a molecule. Please give its molecular formula.
user
C18H7Cl2F6N5O6
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