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Can you give the molecular formula of the molecule (4Z)-3-hydroxy-4-[(1,3,3-trimethylindol-1-ium-2-yl)methylidene]-2-[(E)-(1,3,3-trimethylindol-2-ylidene)methyl]cyclobut-2-en-1-one ?
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C28H29N2O2+
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