You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
For the molecule named 2-(4,6-dimethylpyrimidin-2-yl)sulfanyl-7-ethyl-1-methyl-8-piperazin-1-ylpurin-6-one by IUPAC nomenclature, provide its molecular formula.
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C18H24N8OS
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