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: Dromaeosaurs are part of the theropod group of dinosaurs. 
Sentence2: Birds evolved from a group of bipedal dinosaurs that included Dromaeosaurs.

Output: Dromaeosaurs


Input: Consider Input: Sentence1: Evaporation of sweat uses energy, and the energy comes from body heat. 
Sentence2: Evaporation of sweat uses energy, and the energy comes from exercise.

Output: Evaporation


Input: Consider Input: Sentence1: Bone is less flexible than cartilage but stronger. 
Sentence2: regular skeletons are less flexible than shark skeletons but stronger.


Output: but