You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
1-[4-(cyclopropanecarbonyl)piperazin-1-yl]-2-[cyclopropyl-[(4-ethylphenyl)methyl]amino]ethanone The above is the IUPAC name of a molecule. Write its molecular formula.
user
C22H31N3O2
assistant