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: a light bulb is used for seeing in the dark.
Sentence2: Conventional light bulbs generate light by heating a filament.

Ex Output:
bulb

Ex Input:
Sentence1: if an object is made of a material then that object has the properties of that material.
Sentence2: An object is an item in the real world.

Ex Output:
object

Ex Input:
Sentence1: Once startled, the animal runs away often taking short leaps and emitting low cries.
Sentence2: Loud noises can cause animals to run away.

Ex Output:
away