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: Climate Forests stabilize climate. 
Sentence2: forests stabilize what is generally described in terms of temperature and moisture.

Ex Output:
Forests


Ex Input:
Sentence1: Most fungi get organic compounds from dead organisms. 
Sentence2: Moulds, yeasts, rusts, smuts, mildews, and mushrooms are all types of fungi.

Ex Output:
fungi


Ex Input:
Sentence1: riding a bike does not cause pollution. 
Sentence2: City employees use bicycles on the job to save energy and reduce air pollution.

Ex Output:

pollution