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: Carpools and vanpools can save time. 
Sentence2: vanpools decrease the amount of cars used to travel to a place.

Output: vanpools


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: Boiling is the most reliable way to treat contaminated water. 
Sentence2: Boiling can make water less harmful to drink.


Output: Boiling