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: Infection is what ultimately leads to death. 
Sentence2: scraping oneself on a contaminated object may cause death.

Output: death


Input: Consider Input: Sentence1: Many birds perform elaborate courtship dances. 
Sentence2: Many birds perform dances before they mate.

Output: Many


Input: Consider Input: Sentence1: Girls have played with dolls for generations. 
Sentence2: Girls have used dolls to learn behaviors for generations.


Output: Girls