You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
What is the molecular formula of the compound with this IUPAC name 1-(4-acetylpiperazin-1-yl)-2-[4-(3-cyclopentylpropanoyl)piperazin-1-yl]propan-1-one ?
user
C21H36N4O3
assistant