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: exercise increases a body 's strength. 
Sentence2: Exercise is more than running and lifting.

Output: exercise


Input: Consider Input: Sentence1: Energy enters ecosystems in the form of sunlight or chemical compounds. 
Sentence2: Energy enters ecosystems in the form of photons.

Output: Energy


Input: Consider Input: Sentence1: Shelter or cover is a prime factor. 
Sentence2: Habitat destruction causes animals to move to find cover in another habitat.


Output: cover