You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
For the molecule named [4-[5,6-dimethyl-2-(2-phenylethyl)thieno[2,3-d]pyrimidin-4-yl]piperazin-1-yl]-(3-methoxyphenyl)methanone by IUPAC nomenclature, provide its molecular formula.
user
C28H30N4O2S
assistant