[{"from": "human", "value": "Provide a description of this molecule. [C][C][C][C][C][/C][=C][/C][/C][=C][/C][C][/C][=C][/C][C][C][C][=Branch1][C][=O][O]"}, {"from": "gpt", "value": "The molecule is a polyunsaturated long-chain fatty acid with an 18-carbon backbone and exactly three double bonds, originating from the 6th, 9th and 13th positions from the methyl end."}]