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:
Ligand binding specificities of the eight types and subtypes of the mouse prostanoid receptors expressed in Chinese hamster ovary cells.

Ex Output:
prostanoid


Ex Input:
Cooperative effects for CYP2E1 differ between styrene and its metabolites.

Ex Output:
styrene


Ex Input:
Neuroprotective and anti-inflammatory properties of a coffee component in the MPTP model of Parkinson's disease.

Ex Output:

MPTP