[{"from": "human", "value": "Generate a molecule based on the given description. An antiviral agent used in the treatment of cytomegalovirus retinitis. Foscarnet also shows activity against human herpes viruses and HIV."}, {"from": "gpt", "value": "[C][=Branch1][C][=O][Branch1][C][O][P][=Branch1][C][=O][Branch1][C][O][O]"}]