You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
[1-(2-methylphenyl)-5-(trifluoromethyl)pyrazol-4-yl]-(4-pyridin-2-ylpiperazin-1-yl)methanone is the IUPAC name of a molecule. Please give its molecular formula.
user
C21H20F3N5O
assistant