You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
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For the molecule named 4-(2-aminoethylamino)-11-(3-aminopropylamino)naphtho[2,3-f][1]benzothiole-5,10-dione by IUPAC nomenclature, provide its molecular formula.
user
C21H22N4O2S
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