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.

Input: Consider Input: Sentence1: Amphibians have permeable skin that easily absorbs substances from the environment. 
Sentence2: permeable skin easily absorbs air to breathe through.

Output: absorbs


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

Output: vents


Input: Consider Input: Sentence1: Tides are the rising and falling of ocean's water. 
Sentence2: the gravitational pull of the Moon on Earth 's oceans causes water to rise and fall.


Output: falling