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: Faster metabolism means more calories consumed, and usually, weight loss. 
Sentence2: mammals generate heat by consuming calories.

Output: calories


Input: Consider Input: Sentence1: chemical splashing can cause harm to humans. 
Sentence2: chemical splashing can cause harm to animals.

Output: cause


Input: Consider Input: Sentence1: a plant requires photosynthesis to grow. 
Sentence2: Photosynthesis requires the chlorophyll molecule.


Output: photosynthesis