You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
(2R,3R,4S,5S)-2-(4-pyridin-4-ylpyridin-3-yl)oxythiane-3,4,5-triol The above is the IUPAC name of a molecule. Write its molecular formula.
user
C15H16N2O4S
assistant