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: Results can be damaging or disastrous. 
Sentence2: Lack of immunization can be damaging or disastrous.

Ex Output:
damaging


Ex Input:
Sentence1: With a spatula, fold in flour mixture. 
Sentence2: a sifter is used for separating flour.

Ex Output:
flour


Ex Input:
Sentence1: Carbon Monoxide Carbon monoxide is a health hazard. 
Sentence2: Furnaces and other devices that burn fuel are health hazards.

Ex Output:

hazard