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: Examples are citric acid, tartaric acid, lactic acid and malic acid. 
Sentence2: citric compounds will turn the color of litmus paper from blue to red.

citric