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.

Input: Consider Input: Sentence1: Parasites are organisms that live off a host. 
Sentence2: roundworms may be free-living or live off a host.

Output: host


Input: Consider Input: Sentence1: All photos are digital images. 
Sentence2: satellites are used to take photos from space.

Output: photos


Input: Consider Input: Sentence1: camouflage is used for protection by prey against predators. 
Sentence2: Cryptic coloration is a type of camouflage.


Output: camouflage