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: Flowers produce seeds for reproduction. 
Sentence2: flowers require dispersal for reproduction.

Ex Output:
Flowers


Ex Input:
Sentence1: Mammalian teeth are important for digestion. 
Sentence2: Mammalian teeth are important for gleaning nutrients from food.

Ex Output:

Mammalian