You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
N-[2-[[2-[4-(4-chlorophenyl)-6-oxopyrimidin-1-yl]acetyl]amino]ethyl]-2H-benzotriazole-5-carboxamide The above is the IUPAC name of a molecule. Write its molecular formula.
user
C21H18ClN7O3
assistant