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: dew is formed when water vapor condenses over night. 
Sentence2: dew is formed when cooling  over night.

Ex Output:
dew


Ex Input:
Sentence1: Mammals depend on the vegetation for food and shelter. 
Sentence2: Mammals are Heterotrophs.

Ex Output:
Mammals


Ex Input:
Sentence1: Insulin helps cells take up glucose from the blood. 
Sentence2: protein hormones help cells take up glucose from the blood.

Ex Output:

blood