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: Oxygen fatigue is a shortage of oxygen reaching the brain. 
Sentence2: Plants can reduce fatigue during the daytime.

Output: fatigue


Input: Consider Input: Sentence1: dropping an object into water causes vibrations in the water. 
Sentence2: Dropping an object into lake causes vibrations.

Output: dropping


Input: Consider Input: Sentence1: the looseness of soil has a positive impact on a plant 's roots' growth in that soil. 
Sentence2: looseness of soil has a positive impact on orchids root growth.


Output: growth