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: 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: Basically, heat is energy. 
Sentence2: Head hair is especially important in preventing energy loss from the body.

Ex Output:
energy


Ex Input:
Sentence1: Light source is an ultra-bright, unbreakable LED Bulb. 
Sentence2: LEDs convert electricity into light and heat energy.

Ex Output:

LED