You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
2-[[2-[4-(3,4-dichlorophenyl)piperazin-1-yl]acetyl]amino]-6-methyl-4,5,6,7-tetrahydro-1-benzothiophene-3-carboxamide is the IUPAC name of a molecule. Please give its molecular formula.
user
C22H26Cl2N4O2S
assistant