Generate an overlapping word between the given two sentences. When you find the overlapping words, they don't have to match exactly, e.g., "survival" and "survive" are valid overlapping words. Little words like "the" or "of" don't count! You must generate significant words which are not the stop words.

Ex Input:
Sentence1: Organisms cluster around hydrothermal vents in the ocean floor. 
Sentence2: vents on the ocean floor are powered by heat.

Ex Output:
vents


Ex Input:
Sentence1: disease-causing microbes have a negative impact on the body. 
Sentence2: pathogens have a negative impact on the body.

Ex Output:
body


Ex Input:
Sentence1: Courtship is behavior that is intended to attract a mate. 
Sentence2: Birds secrete estrogen to attract a mate.

Ex Output:

attract