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What is the molecular formula of the compound with this IUPAC name (Z)-7-[(1R,2R,3S,4S)-3-[(E)-3-oxo-4-thiophen-3-ylbut-1-enyl]-7-oxabicyclo[2.2.1]heptan-2-yl]hept-5-enoic acid ?
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C21H26O4S
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