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: All life relies on a relatively narrow range of pH, or acidity. 
Sentence2: humans rely on a relatively narrow range of acidity.

Output: acidity


Input: Consider Input: Sentence1: the moon revolving around the Earth causes the phases of the moon. 
Sentence2: Lets start our discussion of the Moon's phases with the New Moon phase.

Output: phases


Input: Consider Input: Sentence1: an animal requires nutrients to grow and heal. 
Sentence2: Nutrients that promote healing include vitamin C, zinc, copper, vitamin A, and B vitamins.


Output: nutrients