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: if an object in a fluid is more dense than that fluid then that object will sink in that fluid because of gravity. 
Sentence2: Most seeds are more dense than water.

Output: dense


Input: Consider Input: Sentence1: Specialization occurs when competing species evolve different adaptations. 
Sentence2: evolving different adaptations increases survival.

Output: adaptations


Input: Consider Input: Sentence1: Population density is the average number of individuals per unit of area or volume. 
Sentence2: If the number of individuals of a species increases too quickly too much in a fixed area, the species can become extinct.


Output: individuals