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: Some trees are maples. 
Sentence2: planting maples has a positive impact on an ecosystem.

Output: maples


Input: Consider Input: Sentence1: For example, insulin is a protein hormone. 
Sentence2: Insulin is produced in a part of the cell called the ribosome.

Output: insulin


Input: Consider Input: Sentence1: Adult tunicates are barrel-shaped. 
Sentence2: Bluebells are barrel-shaped.


Output: barrel-shaped