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: Polygenic inheritance Polygenic traits are controlled by an unknown number of genes. 
Sentence2: Skin color is inherited from a number of genes.

Output: genes


Input: Consider Input: Sentence1: Nitrogen is found in proteins, nucleic acids, and chlorophyll. 
Sentence2: Nitrogen, as a gas, is colorless, odorless, and a generally inert element.

Output: Nitrogen


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


Output: energy