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: wind is used for producing electricity. 
Sentence2: Winds are caused by pressure differences.

Output: wind


Input: Consider Input: Sentence1: All cells share some of the same structures and basic functions. 
Sentence2: Inside the cell is a structure called the nucleus.

Output: cells


Input: Consider Input: Sentence1: Fertilization takes place inside the female organism. 
Sentence2: Fertilization takes place inside a woman.


Output: Fertilization