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: 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.

Ex Output:
salt


Ex Input:
Sentence1: Polyps usually reproduce asexually. 
Sentence2: Polyps usually reproduce several different ways.

Ex Output:
Polyps


Ex Input:
Sentence1: Stems Stems are the support structures of a plant. 
Sentence2: Support structures of a plant may store water for some plants.

Ex Output:

plant