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: Cells are the units of function in living things. 
Sentence2: living things cannot survive without oxygen.

Output: living


Input: Consider Input: Sentence1: Weather Clear weather usually means good visibility. 
Sentence2: High pressure systems can cause good visibility.

Output: good


Input: Consider Input: Sentence1: Protective hair grows between the toes. 
Sentence2: toes are insulated by hair.


Output: toes