You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
5-benzamido-6-ethyl-1-methyl-3-propan-2-yloxypyrrolo[2,3-b]pyridine-2-carboxylic acid is the IUPAC name of a molecule. Please give its molecular formula.
user
C21H23N3O4
assistant