You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
Can you give the molecular formula of the molecule 3-ethyl-N-[[3-(2-methoxyphenyl)-1,2,4-oxadiazol-5-yl]methyl]bicyclo[3.3.1]nonan-1-amine ?
user
C21H29N3O2
assistant