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 (4Z,13R)-4-ethylidene-13-methyl-8,14-dioxa-10,20,23-triazatetracyclo[13.5.2.12,6.018,21]tricosa-1(20),2,6(23),15(22),16,18(21)-hexaen-9-one .
user
C21H23N3O3
assistant