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: Minerals are chemical elements that are essential for body processes. 
Sentence2: minerals are needed by body processes.

Ex Output:
processes


Ex Input:
Sentence1: the Earth being tilted on its rotating axis causes seasons. 
Sentence2: the planet's orbit and tilt causes seasons.

Ex Output:
seasons


Ex Input:
Sentence1: an earthquake causes the ground to shake. 
Sentence2: Seismic waves are produced by earthquakes.

Ex Output:

earthquake