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: Blood type is important for medical reasons. 
Sentence2: Type O is important for medical reasons.

Output: important


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: Busses and trains are excellent modes of transportation. 
Sentence2: trains are used for moving people.


Output: trains