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: heating an egg causes a chemical reaction in the egg. 
Sentence2: Insects hatch from eggs.

Output: egg


Input: Consider Input: Sentence1: Among families with children the average number of offspring is 1.8. 
Sentence2: information in an organism's chromosomes cause genetic traits to be passed down to that organism's children.

Output: children


Input: Consider Input: Sentence1: Trees are still used for fuel in some places. 
Sentence2: some gymnosperms can be used as fuel.


Output: fuel