You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
Provide the molecular formula for the IUPAC named substance [4-(5,6-dimethylpyrimidin-4-yl)piperazin-1-yl]-(2-pyridin-4-ylpyrimidin-5-yl)methanone .
user
C20H21N7O
assistant