You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
N-[(1S)-1-[(4S,5S)-4-benzyl-5-tert-butyl-4,5-dihydro-1,3-oxazol-2-yl]-2,2-dimethylpropyl]acetamide is the IUPAC name of a molecule. Please give its molecular formula.
user
C21H32N2O2
assistant