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: Contact with infected blood, contaminated needles. 
Sentence2: scraping oneself on an infected needle may cause infection.

Ex Output:
infected


Ex Input:
Sentence1: If the skin is painful, seek medical attention. 
Sentence2: If your skin hurts, your touch receptors will sense differences.

Ex Output:
skin


Ex Input:
Sentence1: When the strings on a guitar vibrate, they transmit their vibrations to the saddle. 
Sentence2: plucking vibrates the saddle.

Ex Output:

saddle