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 5,5-dimethyl-12-phenyl-6-oxa-9-thia-11,15,16,18,20-pentazapentacyclo[11.7.0.02,10.03,8.014,18]icosa-1,3(8),10,12,14,16,19-heptaene into molecular formula.
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C21H17N5OS
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