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: Antibiotics and vaccines are being stockpiled as Britain gears up to meet the bioterrorism threat. 
Sentence2: Antibiotics and vaccines are being stockpiled against another potential threat in the environment.

Ex Output:
Antibiotics


Ex Input:
Sentence1: Infection is what ultimately leads to death. 
Sentence2: scraping oneself on a contaminated object may cause death.

Ex Output:
death


Ex Input:
Sentence1: Intelligence is primarily a genetically inherited trait. 
Sentence2: Intelligence is primarily encoded in DNA.

Ex Output:

Intelligence