You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
[2-[N-(2-cyanoethyl)-4-methylanilino]-2-oxoethyl] 2-[(1R,2R,4R)-2-bicyclo[2.2.1]heptanyl]acetate The above is the IUPAC name of a molecule. Write its molecular formula.
user
C21H26N2O3
assistant