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-(1,3-dihydroxypropan-2-yloxymethyl)-1-(1-oxo-1-phenylpropan-2-yl)purin-6-one is given. What is its corresponding molecular formula?
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C18H21N5O5
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