You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
Provide the molecular formula for the IUPAC named substance 2-[[(Z)-2-cyano-3-(1H-indol-3-yl)prop-2-enoyl]amino]-4,5,6,7-tetrahydro-1-benzothiophene-3-carboxamide .
user
C21H18N4O2S
assistant