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: forming coal requires decaying vegetation. 
Sentence2: Forming fossil fuels requires decaying vegetation.

Ex Output:
decaying


Ex Input:
Sentence1: To keep cut flowers lasting longer, use a commercial florist preservative such as Floralife. 
Sentence2: Dehydrating food is used to make it last longer.

Ex Output:
lasting


Ex Input:
Sentence1: Hormones control many cell activities, so they are very important for homeostasis. 
Sentence2: Temperature regulation is an example of homeostasis.

Ex Output:

homeostasis