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: Interest in fossils is worldwide. 
Sentence2: paleontologists study something with worldwide interest.

Ex Output:
Interest


Ex Input:
Sentence1: Heat and temperature are the same. 
Sentence2: a thermometer is used to measure heat.

Ex Output:
Heat


Ex Input:
Sentence1: Sweat is the result of excessive physical and emotional exertion. 
Sentence2: Excessive physical and emotional exertion decreases an animal's bodily water.

Ex Output:

emotional