You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
[1-[1-(3-chlorophenyl)-5-ethylpyrazole-4-carbonyl]piperidin-4-yl]-pyrrolidin-1-ylmethanone is the IUPAC name of a molecule. Please give its molecular formula.
user
C22H27ClN4O2
assistant