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: Cancer is a disease in which cells divide out of control. 
Sentence2: Cancer is a disease in which cells grow and divide rapidly.

Ex Output:
Cancer


Ex Input:
Sentence1: Most pituitary hormones control other endocrine glands. 
Sentence2: Hormones tell the ovaries to produce eggs.

Ex Output:
hormones


Ex Input:
Sentence1: Additionally, a surveyor s compass was used. 
Sentence2: Natural magnetism is used for pointing north in a surveying tool.

Ex Output:

s