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: Endospores are commonly found in soil and water. 
Sentence2: Dirt is really misplaced soil.

Output: soil


Input: Consider Input: Sentence1: healing requires rest. 
Sentence2: healing requires time.

Output: healing


Input: Consider Input: Sentence1: an image in a mirror is formed by reflecting light. 
Sentence2: An image in a mirror is formed by reflecting electromagnetic energy.


Output: a