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: Mangoes are propagated vegetatively and by seeds. 
Sentence2: animals propagate mangoes.

Ex Output:
Mangoes


Ex Input:
Sentence1: Flowers produce seeds for reproduction. 
Sentence2: flowers require dispersal for reproduction.

Ex Output:
Flowers


Ex Input:
Sentence1: the Earth revolving around the Sun causes the seasons to change on its axis. 
Sentence2: Earth's orbital motion around the sun is key to the leaves of many trees changing colors.

Ex Output:

Earth