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: Consider Input: Sentence1: Macroevolution occurs over geologic time above the level of the species. 
Sentence2: adding new genes with special capability occurs over geologic time above the level of the species.

Output: above


Input: Consider Input: Sentence1: Ovulation is the release of an egg from an ovary. 
Sentence2: The release of an egg during ovulation is used in reproduction.

Output: Ovulation


Input: Consider Input: Sentence1: The glaciers have weathered unique holes in the rock formations. 
Sentence2: A glacier causes weathering on rock formations.


Output: formations