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: If an object is made of a drug, then that object has the properties of that drug.

Ex Output:
made


Ex Input:
Sentence1: bacteria can cause people to become ill. 
Sentence2: bacteria can cause people to die.

Ex Output:
bacteria


Ex Input:
Sentence1: an earthquake causes the ground to shake. 
Sentence2: Earthquakes are caused by movement of the tectonic plates.

Ex Output:

earthquake