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: Some herbivores have more than one stomach. 
Sentence2: Camels are an herbivore.

Ex Output:
herbivores


Ex Input:
Sentence1: Earth's Atmosphere Earth's atmosphere is the layer of gasses that surrounds the earth. 
Sentence2: weather refers to the conditions in the layer of gasses that surrounds the earth.

Ex Output:
earth


Ex Input:
Sentence1: Blood type is important for medical reasons. 
Sentence2: Blood type is important to know prior to surgery.

Ex Output:

Blood