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: Some viruses live in a dormant state inside the body. 
Sentence2: a virus can live in the brain.

Output: viruses


Input: Consider Input: Sentence1: All lizards are reptiles. 
Sentence2: Lizards are tetrapod vertebrates that produce amniotic eggs.

Output: lizards


Input: Consider Input: Sentence1: when a cooler object touches a warmer object , thermal conduction occurs. 
Sentence2: Heat sinks are designed to be cooler than the objects they're in contact with.


Output: cooler