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:
Oxysterol generation and liver X receptor-dependent reverse cholesterol transport: not all roads lead to Rome.

Ex Output:
cholesterol


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

Ex Output:
MPTP


Ex Input:
The induction of mitochondria-mediated apoptosis in cancer cells by ruthenium(ii) asymmetric complexes.

Ex Output:

ruthenium(ii)