[{"from": "human", "value": "Synthesize a molecule that matches the given characteristics. The molecule is a linear polysaccharide made up from alternating D-galactose and 3,6-anhydro-alpha-L-galactopyranose residues joined by alpha-(1->3)- and beta-(1->4)-linkages. It has a role as a marine metabolite. It is functionally related to a galactan."}, {"from": "gpt", "value": "[C][C@H1][C@H1][Branch2][Ring1][C][C@@H1][Branch1][Ring2][O][Ring1][Branch1][C@@H1][Branch1][Branch2][C@@H1][Branch1][Ring2][O][Ring1][#Branch1][O][O][O][C@H1][C@@H1][Branch2][Branch1][O][C@H1][Branch1][=N][C@H1][Branch1][=Branch2][C@H1][Branch1][Ring2][O][Ring1][=Branch1][C][O][O][O][C@H1][C@H1][Branch2][Ring2][Branch1][C@H1][C@@H1][Branch1][O][C@@H1][Branch1][Ring2][O][Ring1][=Branch1][C][O][Ring1][=Branch1][O][C@H1][C@@H1][Branch1][P][C@H1][Branch1][=N][C@H1][Branch1][=Branch2][C@H1][Branch1][Ring2][O][Ring1][=Branch1][C][O][O][O][O][O][O]"}]