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: sonar is used to find the location of an object. 
Sentence2: Surface ships use sonar to locate and track submarines.

Output: location


Input: Consider Input: Sentence1: Results can be damaging or disastrous. 
Sentence2: Lack of immunization can be damaging or disastrous.

Output: damaging


Input: Consider Input: Sentence1: Humans have collected and grown mushrooms for food for thousands of years. 
Sentence2: Edible mushrooms have been used by various cultures for centuries as a food.


Output: food