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: Antibodies are large, Y-shaped proteins that recognize and bind to antigens. 
Sentence2: Some of the antibodies, antophospholipid antibodies, cause blood clots.

Output: Antibodies


Input: Consider Input: Sentence1: Some herbivores have more than one stomach. 
Sentence2: Camels are an herbivore.

Output: herbivores


Input: Consider Input: Sentence1: harming an animal species has a negative impact on the population size of that species. 
Sentence2: weather can have a negative impact on a species' population size.


Output: impact