You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
Translate the chemical IUPAC name (2E)-2-[(2-methoxy-4-morpholin-4-ylphenyl)methylidene]-[1,3]thiazolo[3,2-a]benzimidazol-1-one into its molecular formula.
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C21H19N3O3S
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