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: friction causes the temperature of an object to increase. 
Sentence2: Friction causes the temperature of a toy to increase.

Output: causes


Input: Consider Input: Sentence1: Digestion is the process of breaking down food into components the body can absorb. 
Sentence2: Saliva starts to break down the food.

Output: breaking


Input: Consider Input: Sentence1: adding salt to a solid decreases the freezing point of that solid. 
Sentence2: Salt is expelled from seawater as it freezes at the freezing point.


Output: freezing