You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
tert-butyl (1R,3S)-3-[[2-[4-(3-carbamoylphenyl)-2-fluorophenyl]-1-cyanoethyl]carbamoyl]-2-azabicyclo[2.2.1]heptane-2-carboxylate is the IUPAC name of a molecule. Please give its molecular formula.
user
C28H31FN4O4
assistant