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.

Example Input: Crystal structure of serine dehydratase from rat liver.
Example Output: serine

Example Input: Contribution of the Na+-K+-2Cl- cotransporter NKCC1 to Cl- secretion in rat OMCD.
Example Output: Cl-

Example Input: Loss of Calcium/Calmodulin-Dependent Protein Kinase II Activity in Cortical Astrocytes Decreases Glutamate Uptake and Induces Neurotoxic Release of ATP.
Example Output:
Glutamate