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: All sharks are predators. 
Sentence2: hiding can be used for avoiding sharks.

Output: sharks


Input: Consider Input: Sentence1: a warm front causes cloudy and rainy weather. 
Sentence2: Stratus clouds are associated with a warm front.

Output: front


Input: Consider Input: Sentence1: Individuals of a species normally mate and produce fertile offspring in the wild e. 
Sentence2: Communities consist of populations of different groups that produce fertile offspring.


Output: fertile