You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
(4-nitrophenyl)-(8-thia-2,11,12-triazatricyclo[5.3.3.01,7]trideca-9,12-dien-4-yl)methanone is the IUPAC name of a molecule. Please give its molecular formula.
user
C16H16N4O3S
assistant