You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
Translate the chemical IUPAC name 3-[3-(benzimidazol-1-ylmethyl)phenyl]-5-(5-ethyl-4-nitro-1H-pyrazol-3-yl)-1,2,4-oxadiazole into its molecular formula.
user
C21H17N7O3
assistant