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: The atypical antidepressant mianserin exhibits agonist activity at kappa-opioid receptors.
Example Output: mianserin

Example Input: Breast cancer and steroid metabolizing enzymes: the role of progestogens.
Example Output: steroid

Example Input: Effects of pentosan polysulfate sodium on the estrogen-induced pituitary prolactinoma in Fischer 344 rats.
Example Output:
sodium