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.

Example Input: Sentence1: Weather today is said to be sunny and clear. 
Sentence2: High pressure systems cause it to be sunny.
Example Output: sunny

Example Input: Sentence1: Information on DNA is organized into genes. 
Sentence2: DNA codes for proteins.
Example Output: DNA

Example Input: Sentence1: Blood pH may become unbalanced if the rate of breathing is too fast or too slow. 
Sentence2: blood pH may become unbalanced from aerobic activities.
Example Output:
Blood