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: a switch is used to start the flow of current in an electrical circuit. 
Sentence2: The flow of electrical current powers a light bulb.

Output: current


Input: Consider Input: Sentence1: Specialization occurs when competing species evolve different adaptations. 
Sentence2: evolving different adaptations increases survival.

Output: adaptations


Input: Consider Input: Sentence1: landfills have a negative impact on the environment. 
Sentence2: Less garbage goes into landfills.


Output: landfills