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: Crops are plants that are grown for food or other uses. 
Sentence2: insects destroy plants.

Ex Output:
plants


Ex Input:
Sentence1: the emission of sulfur dioxide causes acid rain. 
Sentence2: the emission of sulfur dioxide causes soil weathering.

Ex Output:
causes


Ex Input:
Sentence1: exercise has a positive impact on a human 's health. 
Sentence2: Endurance exercises Endurance exercises include cycling, running, and swimming.

Ex Output:

exercise