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: First, the bottle is calibrated with a graduated cylinder. 
Sentence2: calibration is performed with a cylinder.

Ex Output:
calibrated


Ex Input:
Sentence1: satellite technology is used for predicting the weather. 
Sentence2: Weather is what it's like outside each day.

Ex Output:

weather