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: moss causes chemical weathering. 
Sentence2: Sphagnum moss mixed with peat moss.

Output: moss


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: Caecilians are amphibians that move just like earthworms. 
Sentence2: amphibians can be found in moist soil near rivers and streams in tropical regions.


Output: amphibians