You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
4-methyl-2-oxo-N-[(3,4,5-trimethoxyphenyl)methyl]-6-thia-1,8-diazatricyclo[7.3.0.03,7]dodeca-3(7),4,8-triene-5-carboxamide is the IUPAC name of a molecule. Please give its molecular formula.
user
C21H23N3O5S
assistant