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: Nitrogen is found in proteins, nucleic acids, and chlorophyll. 
Sentence2: Lawns eat nitrogen.

Output: Nitrogen


Input: Consider Input: Sentence1: if fossils of a water animal or plant are found in a place then that place used to be covered by water in the past. 
Sentence2: Common fossils include plant fossils like ferns.

Output: plant


Input: Consider Input: Sentence1: Moisture is a necessary ingredient for the production of clouds and precipitation. 
Sentence2: clouds are necessary for precipitation.


Output: clouds