[{"from": "human", "value": "Generate a molecule based on this description. The molecule is a member of cephams and a pivaloyloxymethyl ester. It is functionally related to a cephalexin."}, {"from": "gpt", "value": "[C][C][=C][Branch2][Ring2][Ring1][N][C@@H1][Branch2][Ring1][=Branch2][C@@H1][Branch1][Branch1][C][Ring1][Ring2][=O][N][C][=Branch1][C][=O][C@@H1][Branch1][=Branch2][C][=C][C][=C][C][=C][Ring1][=Branch1][N][S][C][Ring2][Ring1][Ring2][C][=Branch1][C][=O][O][C][O][C][=Branch1][C][=O][C][Branch1][C][C][Branch1][C][C][C]"}]