You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
Please write the molecular formula of the molecule 3,3,3-trifluoro-1-[4-[4-[5-(methylamino)pyrido[3,4-b]pyrazin-7-yl]phenyl]piperazin-1-yl]propan-1-one .
user
C21H21F3N6O
assistant