In this task, you are given a sentence. You are expected to recognize the name of any form of chemical substances. Although there might be several correct answers, you need to write one of them.

Ex Input:
Studies on the antioxidant potential of flavones of Allium vineale isolated from its water-soluble fraction.

Ex Output:
flavones


Ex Input:
New oral anticoagulants: comparative pharmacology with vitamin K antagonists.

Ex Output:
vitamin K


Ex Input:
Novel insights on the effect of nicotine in a murine colitis model.

Ex Output:

nicotine