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

Output: Mating


Input: Consider Input: Sentence1: if a neutral atom loses an electron then an atom with a negative charge will be formed. 
Sentence2: Ice crystals that are formed have a negative charge.

Output: charge


Input: Consider Input: Sentence1: Although hair is created by living follicles in the scalp, it's dead. 
Sentence2: living follicles in the scalp is especially important in preventing heat loss from the body.


Output: follicles