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 tert-butyl (1S,2S,4R,5R)-9-(2-phenylpropan-2-yl)-7,9-diazatricyclo[3.3.1.02,4]nonane-7-carboxylate .
user
C21H30N2O2
assistant