[{"from": "human", "value": "Given SMILES, write its number-averaged molecular weight at room temperature and atmospheric pressure. ->  CC1=C(CCCCCCCC)C(CCCCCCCC)=C(C2=CC=C(C3=CC=C(C)S3)S2)S1\n"}, {"from": "gpt", "value": " 500\n"}]