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: Blood type is important for medical reasons. 
Sentence2: Type O is important for medical reasons.

Output: important


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: plant reproduction often requires pollen. 
Sentence2: reproduction requires pollen.


Output: reproduction