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.

Input: Consider Input: DNA topoisomerase IIalpha (TOP2A) inhibitors up-regulate fatty acid synthase gene expression in SK-Br3 breast cancer cells: in vitro evidence for a 'functional amplicon' involving FAS, Her-2/neu and TOP2A genes.

Output: fatty acid


Input: Consider Input: Desvenlafaxine succinate identifies novel antagonist binding determinants in the human norepinephrine transporter.

Output: norepinephrine


Input: Consider Input: Hydrogen peroxide-mediated oxidative stress disrupts calcium binding on calmodulin: more evidence for oxidative stress in vitiligo.


Output: calcium