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: Earthquakes are natural disasters. 
Sentence2: earthquakes can cause animals to leave an environment.

Ex Output:
Earthquakes


Ex Input:
Sentence1: Plants live just about everywhere on Earth. 
Sentence2: epiphytes live everywhere on earth.

Ex Output:
everywhere


Ex Input:
Sentence1: Because food contains energy. 
Sentence2: an organism requires food for growth.

Ex Output:

food