You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
Name the molecular formula for the molecule established as 1-[3-[4-(3,4-difluorophenyl)-1,4-diazepane-1-carbonyl]piperidin-1-yl]propan-1-one using the IUPAC nomenclature.
user
C20H27F2N3O2
assistant