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 2-[(1R)-1-[(4aS,8aS)-1,2,3,4,4a,5,6,7,8,8a-decahydroisoquinolin-2-ium-2-yl]ethyl]-5-(4-nitrophenyl)-1,3,4-oxadiazole .
user
C19H25N4O3+
assistant