You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
(8S)-8-(2,5-dimethoxyphenyl)-10-(4-methylphenyl)-2,4,5,6,7,11,12-heptazatricyclo[7.4.0.03,7]trideca-1(9),3,5,10-tetraen-13-one is the IUPAC name of a molecule. Please give its molecular formula.
user
C21H19N7O3
assistant