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: bacteria can cause people to become ill. 
Sentence2: bacteria can cause people to die.

Ex Output:
bacteria


Ex Input:
Sentence1: Chordates have a complete digestive system and a closed circulatory system. 
Sentence2: animals with jaws have a complete digestive system and a closed circulatory system.

Ex Output:
circulatory


Ex Input:
Sentence1: habitat destruction causes animals to move to find shelter in another habitat. 
Sentence2: habitat destruction causes cows to move to find shelter in another habitat.

Ex Output:

another