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: Diurnal cycles Diurnal cycles are the daily cycles of light and darkness. 
Sentence2: Plants detect and respond to diurnal cycles.

Ex Output:
Diurnal


Ex Input:
Sentence1: dew is formed when water vapor condenses over night. 
Sentence2: When water vapor condenses overnight, the temperature has reached the dew point.

Ex Output:
condenses


Ex Input:
Sentence1: Bamboos are vigorous, rugged plants. 
Sentence2: bamboo detects and responds to the daily cycle of light and darkness.

Ex Output:

Bamboos