You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
2,2,3,5,5,6,8,8,9-nonafluoro-3,6,9-tris(trifluoromethyl)-1,4,7-trioxonane is the IUPAC name of a molecule. Please give its molecular formula.
user
C9F18O3
assistant