[{"from": "human", "value": "Given SMILES, write its weight-averaged molecular weight at normal measurement conditions.. ->  CC1=CC2=C(C(OCCCCCCCC)=C(C=C(C3=C4C(C=C(/C=C(C(OCC(CCCCCCCC)CCCCCCCCCC)=O)/C#N)S4)=C(C)S3)S5)C5=C2OCCCCCCCC)S1\n"}, {"from": "gpt", "value": " 26\n"}]