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: Limestone caves displaying stalactites. 
Sentence2: Limestone caves are formed by depositions.

Ex Output:
Limestone


Ex Input:
Sentence1: Balance is the ability to sense and maintain body position. 
Sentence2: Another part of the inner ear is used for balance.

Ex Output:
Balance


Ex Input:
Sentence1: Translation reads the genetic code in mRNA and makes a protein. 
Sentence2: Translation reads the genetic code in mRNA and makes a nitrogenous compound.

Ex Output:

Translation