You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
Convert the IUPAC name of a molecule 6-ethyl-N-[[(2R,3S)-1-methyl-2-(2-methylpyrazol-3-yl)piperidin-3-yl]methyl]thieno[2,3-d]pyrimidin-4-amine into molecular formula.
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C19H26N6S
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