You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
5-[5-[[2-hydroxyethyl(methyl)amino]methyl]-1H-indol-2-yl]-6-oxo-1H-pyridine-3-carboxylic acid is the IUPAC name of a molecule. Please give its molecular formula.
user
C18H19N3O4
assistant