You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
2-[4-(2,3-dimethylphenyl)piperazin-1-yl]-2-oxo-N-(2-phenylsulfanylphenyl)acetamide is the IUPAC name of a molecule. Please give its molecular formula.
user
C26H27N3O2S
assistant