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: Dinosaur bones, like many other artifacts, are fossilized. 
Sentence2: radioactive dating is used to determine the age of dinosaur bones.

Output: Dinosaur


Input: Consider Input: Sentence1: An organism can gain energy by assimilation or absorption of food. 
Sentence2: Organisms require food for growth.

Output: food


Input: Consider Input: Sentence1: Light seems to travel in rays or beams. 
Sentence2: an image in a mirror is formed by reflecting rays or beams.


Output: beams