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 ethyl 4-[2-[4-[[2-[4-bromo-3-(difluoromethyl)-5-methylpyrazol-1-yl]acetyl]amino]-3-methylpyrazol-1-yl]propanoyl]piperazine-1-carboxylate .
user
C21H28BrF2N7O4
assistant