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: Chemical weathering is the chemical disintigration of rocks. 
Sentence2: moss causes the chemical disintigration of rocks.

Output: chemical


Input: Consider Input: Sentence1: Many birds perform elaborate courtship dances. 
Sentence2: Many birds perform dances before they mate.

Output: Many


Input: Consider Input: Sentence1: Producers make food from inorganic molecules. 
Sentence2: Decomposition helps producers make food.


Output: Producers