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: For instance, glucose is a sugar. 
Sentence2: insulin helps cells take up sugar from the blood.

Ex Output:
sugar


Ex Input:
Sentence1: a warm front causes cloudy and rainy weather. 
Sentence2: Stratus clouds are associated with a warm front.

Ex Output:
front


Ex Input:
Sentence1: being exposed to wind can cause erosion of soil. 
Sentence2: Construction and destruction Destruction is surface weathering , erosion , etc.

Ex Output:

erosion