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.

Input: Consider Input: Sentence1: Organisms that live in marine biomes must be adapted to the salt in the water. 
Sentence2: Most of the water on the planet is salt water in the oceans.

Output: salt


Input: Consider Input: Sentence1: Pregnancy is the carrying of one or more offspring from fertilization until birth. 
Sentence2: An elephant carries their offspring from fertilization until birth, 22 months later.

Output: fertilization


Input: Consider Input: Sentence1: when metal conducts heat , that metal expands. 
Sentence2: When heat passes through metal, that metal expands.


Output: expands