You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
1-[(2,5-difluorophenyl)methyl]-3-[2-(3,5-dioxo-4-azatricyclo[5.2.1.02,6]dec-8-en-4-yl)ethyl]-2-methylguanidine The above is the IUPAC name of a molecule. Write its molecular formula.
user
C20H22F2N4O2
assistant