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: Chordates have a complete digestive system and a closed circulatory system. 
Sentence2: animals with jaws have a complete digestive system and a closed circulatory system.

Output: circulatory


Input: Consider Input: Sentence1: if an object is made of a material then that object has the properties of that material. 
Sentence2: An object is an item in the real world.

Output: object


Input: Consider Input: Sentence1: Some parasites kill their host, but most do not. 
Sentence2: Parasites include lungworms and GI parasites.


Output: parasites