You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
3-[4-[4-(2-amino-2-oxoethyl)phenyl]phenyl]-4-cyano-5-ethylthiophene-2-carboxylic acid The above is the IUPAC name of a molecule. Write its molecular formula.
user
C22H18N2O3S
assistant