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: Light is the visible form of electromagnetic energy. 
Sentence2: Electromagnetic energy enters the eye through an opening called the pupil.

Output: electromagnetic


Input: Consider Input: Sentence1: Some birds are pollinators that co-evolved with plants. 
Sentence2: insects pollinate plants.

Output: plants


Input: Consider Input: Sentence1: carpooling decreases the amount of cars used to travel to a place. 
Sentence2: Cars are a significant source of air pollution.


Output: cars