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: bacteria can cause people to become ill. 
Sentence2: bacteria can cause people to die.

Output: bacteria


Input: Consider Input: Sentence1: Protozoa make humans sick when they become human parasites. 
Sentence2: paramecium are single celled animals that make humans sick when they become human parasites.

Output: become


Input: Consider Input: Sentence1: Ethanol is produced by alcoholic fermentation of the glucose in corn or other plants. 
Sentence2: A transportation fuel is produced by alcoholic fermentation of the glucose in corn or other plants.


Output: alcoholic