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: Flies are insects with two wings. 
Sentence2: Flies are arthropods with two wings.

Output: Flies


Input: Consider Input: Sentence1: riding a bike does not cause pollution. 
Sentence2: riding a bike does not release particles.

Output: bike


Input: Consider Input: Sentence1: if an object is kicked then force is exerted on that object. 
Sentence2: if an object is kicked then a measurement of newtons is exerted on that object.


Output: exerted