Definition: 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: Sentence1: Plants use unsaturated fatty acids to store energy. 
Sentence2: Among the unsaturated fatty acids are compounds with one, two or three double bonds.

fatty