You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
(4R,5S,6S)-6-[(1R)-1-hydroxyethyl]-4-methyl-7-oxo-3-[[2-(pyridin-4-ylamino)-1,4,5,6-tetrahydropyrimidin-5-yl]sulfanyl]-1-azabicyclo[3.2.0]hept-2-ene-2-carboxylic acid is the IUPAC name of a molecule. Please give its molecular formula.
user
C19H23N5O4S
assistant