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: a battery converts chemical energy into electrical energy. 
Sentence2: Battery electricity comes conversion.

Output: battery


Input: Consider Input: Sentence1: All lizards are reptiles. 
Sentence2: Lizards are tetrapod vertebrates that produce amniotic eggs.

Output: lizards


Input: Consider Input: Sentence1: Mammary glands are used to produce milk to nourish their young. 
Sentence2: Female mammals have glands are used to produce milk to nourish their young.


Output: glands