[{"from": "human", "value": "Write number-averaged molecular weight of given SMILES at normal measurement conditions.. ->  CC(S1)=CC2=C1C(OCCCCCCCCCCCC)=C(C=C(C3=CC=C(C)C4=NSN=C43)S5)C5=C2OCCCCCCCCCCCC\n"}, {"from": "gpt", "value": " 18.5\n"}]