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: Conventional myosin is required for cytokinesis . 
Sentence2: Conventional myosin is required for the final stage of cell division.

Output: Conventional


Input: Consider Input: Sentence1: Cells are the units of function in living things. 
Sentence2: living things cannot survive without oxygen.

Output: living


Input: Consider Input: Sentence1: Extinct animals include the dodo bird and the saber-toothed tiger. 
Sentence2: The last dodo birds could not produce offspring.


Output: bird