You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
(3R,4R,5S)-2-(hydroxymethyl)-1-[6-[(5-imidazol-1-ylpyridin-2-yl)amino]hexyl]piperidine-3,4,5-triol The above is the IUPAC name of a molecule. Write its molecular formula.
user
C20H31N5O4
assistant