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: Autumn brings the changing of the seasons. 
Sentence2: Earth 's tilt on its rotating axis causes autumn.

Ex Output:
Autumn


Ex Input:
Sentence1: Endospores are commonly found in soil and water. 
Sentence2: Dirt is really misplaced soil.

Ex Output:
soil


Ex Input:
Sentence1: Viruses are incapable of reproducing on their own. 
Sentence2: viruses cannot procreate.

Ex Output:

Viruses