You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
(1S,3R,4S)-2-(4,7-difluoro-1H-indole-2-carbonyl)-5,5-difluoro-N-[(E,2R)-4-fluoro-4-methylsulfonyl-1-[(3R)-2-oxopyrrolidin-3-yl]but-3-en-2-yl]-2-azabicyclo[2.2.2]octane-3-carboxamide The above is the IUPAC name of a molecule. Write its molecular formula.
user
C26H27F5N4O5S
assistant