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: Bacteria and Viruses Bacteria and viruses can cause diseases. 
Sentence2: bacteria can have a negative impact on an organism.

Ex Output:
Bacteria


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: For example, the word Car refers to a type of object, so Car is a class. 
Sentence2: Friction causes a car to lose energy.

Ex Output:

Car