You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
2-ethyl-5-[[4-[[3-(trifluoromethyl)phenyl]methyl]piperazin-1-yl]methyl]-1,3,4-oxadiazole is the IUPAC name of a molecule. Please give its molecular formula.
user
C17H21F3N4O
assistant