You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
1-[2-(3,5-difluorophenyl)ethyl]-3-[2-[[5-(trifluoromethyl)pyridin-2-yl]amino]ethyl]urea The above is the IUPAC name of a molecule. Write its molecular formula.
user
C17H17F5N4O
assistant