You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
N-[[(2R,3S)-2-(1-methylimidazol-2-yl)oxan-3-yl]methyl]-1H-pyrrolo[2,3-b]pyridine-2-carboxamide The above is the IUPAC name of a molecule. Write its molecular formula.
user
C18H21N5O2
assistant