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: Average vehicle speed rises by only 0.3 miles per hour. 
Sentence2: a speedometer measures miles per hour.

Output: hour


Input: Consider Input: Sentence1: the emission of sulfur dioxide causes acid rain. 
Sentence2: the emission of sulfur dioxide causes soil weathering.

Output: causes


Input: Consider Input: Sentence1: Passive immunity lasts only as long as the antibodies survive in body fluids. 
Sentence2: Passive immunity lasts only as long as the antibodies survive in fluid contaminated with blood.


Output: Passive