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: Skin color is another polygenic trait. 
Sentence2: Skin color is influenced by multiple genes.

Output: Skin


Input: Consider Input: Sentence1: Cells are programmed to divide only a set number of times. 
Sentence2: Cells reproduce asexually, by dividing.

Output: divide


Input: Consider Input: Sentence1: a beak is used for catching prey by some birds. 
Sentence2: Hunting often at night, caracals depend on stealth to catch prey.


Output: catching