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.

Example Input: Sentence1: decomposition increases the amount of nutrients in the soil. 
Sentence2: decomposition increases the amount of cations.
Example Output: amount

Example Input: Sentence1: Macroevolution is more than repeated rounds of microevolution. 
Sentence2: evolution over geologic time above the level of the species is more than repeated rounds of microevolution.
Example Output: microevolution

Example Input: Sentence1: Algae have varied life cycles. 
Sentence2: primitive green plants have varied life cycles.
Example Output:
cycles