You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
2-(4-methoxyphenyl)-1-[(1S,9R)-8-oxa-2,3,4,12-tetrazatricyclo[7.4.0.02,6]trideca-3,5-dien-12-yl]ethanone is the IUPAC name of a molecule. Please give its molecular formula.
user
C17H20N4O3
assistant