You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
5-[1-(2-chloro-3,6-difluorophenyl)ethyl]-3-[4-(4-methylpiperazin-1-yl)phenoxy]-6,7,8,9-tetrahydropyrazino[2,3-b][1,4]diazepine is the IUPAC name of a molecule. Please give its molecular formula.
user
C26H29ClF2N6O
assistant