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: Eggs are usually laid in a nest. 
Sentence2: birds have nests.

Output: nest


Input: Consider Input: Sentence1: smell is used for finding food by some animals. 
Sentence2: Food includes small rodents and birds.

Output: food


Input: Consider Input: Sentence1: Eyes detect light, organized into images that fall on the retina. 
Sentence2: Eyes can detect images and see light using sight.


Output: detect