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: the emission of sulfur dioxide causes acid rain. 
Sentence2: Sulfur dioxide emissions causes soil nutrients to be leached away.

Output: dioxide


Input: Consider Input: Sentence1: Osteoporosis is a disease characterized by a decrease in bone mineral density. 
Sentence2: a disease in which osteoclasts are more active than osteoblasts results in a decrease in bone mineral density.

Output: bone


Input: Consider Input: Sentence1: thirst is used to make an animal realize that it needs to replenish its bodily water by the body. 
Sentence2: Every body needs plenty of hydration, and water is the best source of that hydration.


Output: water