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.

Input: Consider Input: Sentence1: sonar is used to find the location of an object. 
Sentence2: Surface ships use sonar to locate and track submarines.

Output: location


Input: Consider Input: Sentence1: Insect wings are attached to the dorsal side of their thorax. 
Sentence2: wings are attached to the dorsal side of the insect.

Output: dorsal


Input: Consider Input: Sentence1: ultraviolet light causes sunburn. 
Sentence2: Exposure to ultraviolet light can be relieved with cold vinegar.


Output: light