You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
Translate the chemical IUPAC name 1-[(3aR,6aR)-3a-(5-ethyl-1,3,4-oxadiazol-2-yl)-1,3,4,5,6,6a-hexahydrocyclopenta[c]pyrrole-2-carbonyl]-3-methylcyclobutane-1-carbonitrile into its molecular formula.
user
C18H24N4O2
assistant