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: the uterus is used in reproduction. 
Sentence2: Reproduction uses the same organ as menstruation.

Ex Output:
reproduction


Ex Input:
Sentence1: Without light there is no sense of vision. 
Sentence2: Glass causes a sense of vision.

Ex Output:

sense