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:
Evaluation of drug interactions of GSK1292263 (a GPR119 agonist) with statins: from in vitro data to clinical study design.

Ex Output:
GSK1292263


Ex Input:
Rapid quantitation of plasma 2'-deoxyuridine by high-performance liquid chromatography/atmospheric pressure chemical ionization mass spectrometry and its application to pharmacodynamic studies in cancer patients.

Ex Output:
2'-deoxyuridine


Ex Input:
Crystal structure of serine dehydratase from rat liver.

Ex Output:

serine