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: Ovulation is the release of an egg from an ovary. 
Sentence2: The release of an egg during ovulation is used in reproduction.

Ex Output:
Ovulation


Ex Input:
Sentence1: a solution is formed by one substance being dissolved in another substance. 
Sentence2: A solution is formed when limestone is dissolved in ocean water.

Ex Output:
formed


Ex Input:
Sentence1: Organic Matter Organic matter is the varied array of carbon-containing compounds in the soil. 
Sentence2: Decomposition increases the amount of carbon-containing compounds in the soil.

Ex Output:

carbon-containing