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: Generally, pheromones are volatile substances. 
Sentence2: Male dogs use volatile substances in urine to mark their territory.

Output: substances


Input: Consider Input: Sentence1: All monkeys are mammals. 
Sentence2: monkeys conserve body heat with their hair or fur.

Output: monkeys


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


Output: corn