[{"from": "human", "value": "Describe this molecule. [C][Branch1][=Branch2][/C][=C][/C][C][=Branch1][C][=O][O][C][=Branch1][C][=O][O]"}, {"from": "gpt", "value": "The molecule is a hexenedioic acid where the C=C double bond is located at the 3-position."}]