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: if fossils of a water animal or plant are found in a place then that place used to be covered by water in the past. 
Sentence2: Fossils of a water animal or plant are located in water-laid sediments.

Output: animal


Input: Consider Input: Sentence1: After the algae complete their life cycle and die bacteria consume the dead algae. 
Sentence2: bacteria eat algae.


Output: bacteria