You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
tert-butyl N-[(2S,3R)-4-hydroxy-3-methyl-1-[4-(2-methylpropyl)phenyl]butan-2-yl]carbamate The above is the IUPAC name of a molecule. Write its molecular formula.
user
C20H33NO3
assistant