You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
2-[ethyl-[(4-oxo-6-phenyl-3H-thieno[2,3-d]pyrimidin-2-yl)methyl]amino]-N-[2-(trifluoromethyl)phenyl]acetamide is the IUPAC name of a molecule. Please give its molecular formula.
user
C24H21F3N4O2S
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