You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
N-(2,5-dimethylphenyl)-2-[(8,11,11-trimethyl-3,4,6-triazatricyclo[6.2.1.02,7]undeca-2(7),3,5-trien-5-yl)sulfanyl]acetamide is the IUPAC name of a molecule. Please give its molecular formula.
user
C21H26N4OS
assistant