You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
Translate the chemical IUPAC name (6S,8R,9S,10R,13S,14S,17R)-17-acetyl-17-bromo-6-fluoro-10,13-dimethyl-2,6,7,8,9,11,12,14,15,16-decahydro-1H-cyclopenta[a]phenanthren-3-one into its molecular formula.
user
C21H28BrFO2
assistant