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: An example of a cartilaginous fish is a shark. 
Sentence2: jaws make sharks excellent predators.

Output: shark


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: Scotland s lochs , including the famous Loch Ness, are glacial lakes. 
Sentence2: Lochs are bigger and deeper than ponds.


Output: Loch