You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
6-ethyl-5-(4-fluorophenyl)-1-methyl-4-oxo-3-propan-2-yloxypyrrolo[3,2-c]pyridine-2-carboxylic acid The above is the IUPAC name of a molecule. Write its molecular formula.
user
C20H21FN2O4
assistant