You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
Translate the chemical IUPAC name 5-(5-methylsulfonylpyridin-2-yl)-N-[(3R)-piperidin-3-yl]-1H-pyrrolo[2,3-b]pyridin-4-amine into its molecular formula.
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C18H21N5O2S
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