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: Weather Clear weather usually means good visibility. 
Sentence2: High pressure systems can cause good visibility.

Output: good


Input: Consider Input: Sentence1: Ozone depletion results in higher levels of UV radiation reaching Earth. 
Sentence2: less ozone means more ultraviolet light.

Output: Ozone


Input: Consider Input: Sentence1: Water is made up of H2O molecules. 
Sentence2: h2o is essential for all life on Earth.


Output: H2O