You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
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Under IUPAC nomenclature, a molecule named 2-amino-9-[(1S,6R,8R,10R,15S,17R)-8-(7-aminoimidazo[4,5-b]pyridin-3-yl)-12-hydroxy-3-oxo-3-sulfanyl-12-sulfanylidene-2,4,7,11,13,16-hexaoxa-3lambda5,12lambda5-diphosphatricyclo[13.2.1.06,10]octadecan-17-yl]-1H-purin-6-one is given. What is its corresponding molecular formula?
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C21H25N9O9P2S2
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