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: Plants live just about everywhere on Earth. 
Sentence2: epiphytes live everywhere on earth.

Output: everywhere


Input: Consider Input: Sentence1: a fire requires oxygen to burn. 
Sentence2: Oxygen has  eight protons and eight electrons.

Output: oxygen


Input: Consider Input: Sentence1: if a neutral atom loses an electron then an atom with a negative charge will be formed. 
Sentence2: Atoms are the smallest units of elements.


Output: atom