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: a flashlight converts chemical energy into light energy. 
Sentence2: Only as long as there are batteries in the flashlight, the flashlight will function.

Ex Output:
flashlight


Ex Input:
Sentence1: Trees have woody stems covered with bark. 
Sentence2: Evergreens have woody stems covered with bark.

Ex Output:
bark


Ex Input:
Sentence1: information in an organism 's chromosomes cause genetic traits to be passed down to that organism 's offspring. 
Sentence2: Intelligence is primarily a genetically inherited trait.

Ex Output:

genetic