You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
Convert the IUPAC name of a molecule 3-[(2,4-dichlorophenyl)methyl]-5-(4-ethoxyphenyl)-6-methylthieno[2,3-d]pyrimidin-4-one into molecular formula.
user
C22H18Cl2N2O2S
assistant