You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
For the molecule named 2-[(4R)-1-[(1S)-1-[4-(2,4-difluorophenyl)phenyl]ethyl]-4-(4-fluorophenyl)-2-oxopiperidin-4-yl]ethylurea by IUPAC nomenclature, provide its molecular formula.
user
C28H28F3N3O2
assistant