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: Ice is frozen water. 
Sentence2: ice expands.

Output: Ice


Input: Consider Input: Sentence1: Passive immunity lasts only as long as the antibodies survive in body fluids. 
Sentence2: A pregnant woman will pass antibodies to the fetus.

Output: antibodies


Input: Consider Input: Sentence1: Hookworms can be fatal to puppies. 
Sentence2: Larvae can be fatal to puppies.


Output: fatal