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: friction causes the temperature of an object to increase. 
Sentence2: pressure causes the temperature of an object to increase.

Ex Output:
causes


Ex Input:
Sentence1: Energy is the fuel for chemical reactions which run the various systems of the body. 
Sentence2: running requires fuel for chemical reactions which run the various systems of the body.

Ex Output:
body


Ex Input:
Sentence1: For many, adolescence is synonymous with puberty. 
Sentence2: growth is faster during infancy than adolescence.

Ex Output:

adolescence