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.

Ex Input:
Sentence1: Carbon cycles quickly between organisms and the atmosphere. 
Sentence2: the atmosphere is essential to all living organisms.

Ex Output:
organisms


Ex Input:
Sentence1: killing microorganisms in food can be used to extend the shelf life of that food. 
Sentence2: Cooking can be used to extend the shelf life of food.

Ex Output:
be


Ex Input:
Sentence1: sedimentary rocks are formed by deposition. 
Sentence2: sandstone is formed by deposition.

Ex Output:

by