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-chloro-6-[(4-ethylsulfonylphenyl)methylamino]-8-[(3S)-oxolan-3-yl]pteridin-7-one is given. What is its corresponding molecular formula?
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C19H20ClN5O4S
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