You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
Please write the molecular formula of the molecule (6R,7R)-3-cyclopropyl-8-oxo-7-[(2-phenoxyacetyl)amino]-5-thia-1-azabicyclo[4.2.0]oct-2-ene-2-carboxylic acid .
user
C18H18N2O5S
assistant