You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
2-chloro-6-ethyl-5-(4-ethylphenyl)-N-methyl-N-(2-pyridin-4-ylethyl)thieno[2,3-d]pyrimidin-4-amine is the IUPAC name of a molecule. Please give its molecular formula.
user
C24H25ClN4S
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