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: the color of leaves on deciduous trees usually changes in the autumn season. 
Sentence2: Common deciduous trees are the oak, elm and beech.

deciduous