[{"from": "human", "value": "Generate a molecule based on this description. The molecule is a homocystine zwitterion in which both stereocentres have L configuration. It is a tautomer of a L,L-homocystine."}, {"from": "gpt", "value": "[C][Branch1][#C][C][S][S][C][C][C@@H1][Branch1][=Branch1][C][=Branch1][C][=O][O-1][NH3+1][C@@H1][Branch1][=Branch1][C][=Branch1][C][=O][O-1][NH3+1]"}]