You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
Please write the molecular formula of the molecule 2-[4-bromo-5-cyclopropyl-3-(trifluoromethyl)pyrazol-1-yl]-1-[4-[(3-fluorophenyl)methyl]piperazin-1-yl]ethanone .
user
C20H21BrF4N4O
assistant