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: Producers use energy and inorganic molecules to make food. 
Sentence2: Green plants use energy and inorganic molecules to make food.

Output: energy


Input: Consider Input: Sentence1: webbed feet are used for moving faster through water by aquatic animals. 
Sentence2: Feet designed for swimming are used for moving faster through water.


Output: faster