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: Specialization decreases mortality 12,13 and increases survival. 
Sentence2: evolving different adaptations increases survival.

Output: increases


Input: Consider Input: Sentence1: an animal requires air for survival. 
Sentence2: It is breathed in by animals and restored to the air by the photosynthesis mechanism of plants.

Output: air


Input: Consider Input: Sentence1: the movement of tectonic plates causes volcanic eruptions. 
Sentence2: tectonic plate movement can lead to debris flows.


Output: movement