You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
Name the molecular formula for the molecule established as (E)-3-(2,3-dihydroimidazo[4,5-b]pyridin-1-yl)-N-methyl-N-[(1-methylindol-2-yl)methyl]prop-2-enamide using the IUPAC nomenclature.
user
C20H21N5O
assistant