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: Absorption of nutrients occurs mainly in the small intestine. 
Sentence2: The small intestine is the main place where food absorption occurs.

Ex Output:
intestine


Ex Input:
Sentence1: a flashlight converts chemical energy into light energy. 
Sentence2: Only as long as there are batteries in the flashlight, the flashlight will function.

Ex Output:
flashlight


Ex Input:
Sentence1: The earthquake produced severe building damage. 
Sentence2: earthquakes can damage buildings.

Ex Output:

building