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 magnet moving in a coil of copper wire can cause an electric current. 
Sentence2: An electric current forms when a magnet is run through an induction coil.

Ex Output:
current


Ex Input:
Sentence1: riding a bike does not cause pollution. 
Sentence2: riding a bike does not release particles.

Ex Output:
bike


Ex Input:
Sentence1: Flood waters rise rapidly. 
Sentence2: heavy rains cause waters to rise rapidly.

Ex Output:

rapidly