You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
15-chloro-9-(methoxymethyl)-5-[2-(2-methyl-1H-imidazol-5-yl)ethynyl]-2,4,8,10,11-pentazatetracyclo[11.4.0.02,6.08,12]heptadeca-1(13),3,5,9,11,14,16-heptaene is the IUPAC name of a molecule. Please give its molecular formula.
user
C20H16ClN7O
assistant