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: boiling is when liquids are heated above their boiling point. 
Sentence2: If the pressure is reduced, the boiling point is lowered.

Output: boiling


Input: Consider Input: Sentence1: Oil and gasoline are fossil fuels. 
Sentence2: lawn mowers convert fossil fuels into motion.

Output: fossil


Input: Consider Input: Sentence1: For the nonrenewable resources, depletion means extraction of the available natural resources. 
Sentence2: soil nutrition can be extracted.


Output: extraction