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: when electricity flows to a light bulb , the light bulb will turn on. 
Sentence2: water pumps can turn on light bulbs.

Output: bulb


Input: Consider Input: Sentence1: killing microorganisms in food can be used to extend the shelf life of that food. 
Sentence2: Cooking can be used to extend the shelf life of food.

Output: be


Input: Consider Input: Sentence1: DNA is copied in connection with celldivision. 
Sentence2: DNA replication is connected with celldivision.


Output: celldivision