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: Secondary accidents are a major problem under driving conditions of reduced visibility. 
Sentence2: Bad weather increases the risk of car accidents.

Output: Secondary


Input: Consider Input: Sentence1: Very often their only metal object in the house is a cooking pot or a knife. 
Sentence2: sharpening a knife causes it to change shape.

Output: knife


Input: Consider Input: Sentence1: Thyroid hormone and growth hormone affect hair growth. 
Sentence2: that which is responsible for hair growth are regulated by feedback mechanisms.


Output: growth