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: keeping food cold is used for keeping food fresh. 
Sentence2: Keeping food at 40 degrees F or lower is used for keeping food fresh.

Output: food


Input: Consider Input: Sentence1: Polyps usually reproduce asexually. 
Sentence2: Polyps usually reproduce several different ways.

Output: Polyps


Input: Consider Input: Sentence1: Plastics are made from petroleum and produce toxic waste. 
Sentence2: Plastic bags are made from non-renewable petroleum resources.


Output: made