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: sharpening an object causes that object to change shape. 
Sentence2: sharpening a knife causes it to change shape.

Ex Output:
causes


Ex Input:
Sentence1: Some viruses live in a dormant state inside the body. 
Sentence2: a virus can live in the brain.

Ex Output:
viruses


Ex Input:
Sentence1: Babies that are very large or very small at birth are less likely to survive. 
Sentence2: Babies that are very large or very small at birth are less likely to live.

Ex Output:

Babies