You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
Translate the chemical IUPAC name (2S)-3-amino-2-(4-chlorophenyl)-1-[4-[(7R)-7-hydroxy-5-methyl-6,7-dihydro-5H-cyclopenta[d]pyrimidin-4-yl]piperazin-1-yl]propan-1-one into its molecular formula.
user
C21H26ClN5O2
assistant