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: hunting requires seeing prey. 
Sentence2: hunting requires seeing an animal.

Output: hunting


Input: Consider Input: Sentence1: Lymph is a fluid that leaks out of capillaries into spaces between cells. 
Sentence2: Humans are made up of trillions of cells.

Output: cells


Input: Consider Input: Sentence1: Humans are complex organisms. 
Sentence2: spores may be dispersed by humans.


Output: Humans