You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
For the molecule named 1-N,1-N,7-N,7-N-tetraethyl-2,3,4,6,8,9-hexafluorophenazine-1,7-diamine by IUPAC nomenclature, provide its molecular formula.
user
C20H20F6N4
assistant