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 3-[(4aR,8aR)-7-acetyl-4a-hydroxy-3,4,5,6,8,8a-hexahydro-1H-2,7-naphthyridin-2-yl]-5-phenyl-1,2-oxazole-4-carboxylic acid .
user
C20H23N3O5
assistant