You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
Convert the IUPAC name of a molecule methyl 2-[[(3R)-6-chloro-3,4-dihydro-2H-chromen-3-yl]carbamoyl]-6,7-dihydro-5H-pyrazolo[5,1-b][1,3]oxazine-5-carboxylate into molecular formula.
user
C18H18ClN3O5
assistant