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: information in an organism 's chromosomes cause genetic traits to be passed down to that organism 's offspring. 
Sentence2: information in Man's chromosomes cause genetic traits to be passed down to offspring.

Ex Output:
chromosomes


Ex Input:
Sentence1: protein is used to repair cells by the human body. 
Sentence2: Wound healing requires protein.

Ex Output:
protein


Ex Input:
Sentence1: Playing is one way mammals and other animals learn how to behave. 
Sentence2: playing is one way opossums learn how to behave.

Ex Output:

Playing