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: Contact with infected blood, contaminated needles. 
Sentence2: scraping oneself on an infected needle may cause infection.

Output: infected


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: Caecilians can be found in moist soil near rivers and streams in tropical regions. 
Sentence2: Caecilians are amphibians that move just like earthworms.


Output: Caecilians