You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
Can you give the molecular formula of the molecule 2-ethyl-1-[4-[2-methyl-6-[(4-methylpyridin-2-yl)amino]pyrimidin-4-yl]piperazin-1-yl]butan-1-one ?
user
C21H30N6O
assistant