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.

Ex Input:
Sentence1: the ovaries are used in reproduction. 
Sentence2: Egg released by the ovary.

Ex Output:
ovaries


Ex Input:
Sentence1: an earthquake causes the ground to shake. 
Sentence2: A number of buildings in Istanbul also were damaged in the earthquake.

Ex Output:
earthquake


Ex Input:
Sentence1: a plant requires sunlight to grow. 
Sentence2: Vegetables require sunlight to grow.

Ex Output:

grow