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: Adaptation traits contribute to individual fitness and to the evolution of animal genetic resources. 
Sentence2: Behaviors can improve the evolution of animal genetic resources.

Output: animal


Input: Consider Input: Sentence1: First, the bottle is calibrated with a graduated cylinder. 
Sentence2: calibration is performed with a cylinder.

Output: calibrated


Input: Consider Input: Sentence1: Many animals have developed ways of getting rid of extra heat by sweating or panting. 
Sentence2: Many animals  ways of getting rid of extra heat  makes bodily water decrease.


Output: extra