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.

Ex Input:
Sentence1: melting is when solids are heated above their melting point. 
Sentence2: Ice is a solid, it's cold and it's hard.

Ex Output:
solids


Ex Input:
Sentence1: Most copepods feed on phytoplankton. 
Sentence2: most copepods feed on bacteria and algae that use sunlight to make food.

Ex Output:
copepods


Ex Input:
Sentence1: Annual desert plants germinate, grow, and flower quickly when there is a rainy year. 
Sentence2: wet weather helps plants germinate.

Ex Output:

germinate