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 1-[4-(3-chlorobenzoyl)piperazin-1-yl]-3-(3-pyridin-3-yl-1,2,4-oxadiazol-5-yl)propan-1-one .
user
C21H20ClN5O3
assistant