You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
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Convert the IUPAC name of a molecule (6S)-6-(2,6-dichlorophenyl)-3-methylsulfanyl-7-propanoyl-2,6-dihydro-[1,2,4]triazino[1,6-c]quinazolin-5-ium-1-one into molecular formula.
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C20H17Cl2N4O2S+
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