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: faulting of rock in Earth 's crust causes earthquakes. 
Sentence2: fault movement forms earthquakes.

Ex Output:
earthquakes


Ex Input:
Sentence1: Veins generally carry deoxygenated blood. 
Sentence2: Blood carries blood cells.

Ex Output:
blood


Ex Input:
Sentence1: Diatomes are a type of single celled algae. 
Sentence2: diatomes have varied life cycles.

Ex Output:

Diatomes