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: Chromosomes are the form of the genetic material of a cell during cell division. 
Sentence2: Microtubules move the genetic material of a cell during cell division.

Ex Output:
cell


Ex Input:
Sentence1: Weather Clear weather usually means good visibility. 
Sentence2: High pressure systems can cause good visibility.

Ex Output:
good


Ex Input:
Sentence1: Earthy sediment of fine particles of rock and soil suspended in and carried by water. 
Sentence2: Oil is formed by fine particles pushing down on algae.

Ex Output:

fine