You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
tert-butyl 2-ethyl-4-(1H-pyrrolo[2,3-b]pyridin-4-yl)-5,7-dihydropyrrolo[3,4-d]pyrimidine-6-carboxylate The above is the IUPAC name of a molecule. Write its molecular formula.
user
C20H23N5O2
assistant