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: Batteries are a better source of DC electricity. 
Sentence2: a flashlight requires batteries to produce light.

Output: Batteries


Input: Consider Input: Sentence1: Trees have woody stems covered with bark. 
Sentence2: Evergreens have woody stems covered with bark.

Output: bark


Input: Consider Input: Sentence1: zinc has a positive impact on the healing of wounds. 
Sentence2: Foods that are high in zinc are oysters.


Output: zinc