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: Mitosis is cell division. 
Sentence2: Chromosomes are the form of the genetic material of a cell during mitosis.

Output: Mitosis


Input: Consider Input: Sentence1: Mating is generally preceded by courtship. 
Sentence2: Mating is generally similar across species.

Output: Mating


Input: Consider Input: Sentence1: Protozoa make humans sick when they become human parasites. 
Sentence2: Exhibit One-celled animals are called protozoa .


Output: Protozoa