You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
tert-butyl (1R,4S)-6-oxo-1-(phenylmethoxymethyl)-2,5-diazabicyclo[2.2.1]heptane-2-carboxylate is the IUPAC name of a molecule. Please give its molecular formula.
user
C18H24N2O4
assistant