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: cell division often causes growth. 
Sentence2: Mitosis is cell division.

Output: cell


Input: Consider Input: Sentence1: Some mollusks are nearly microscopic. 
Sentence2: Some squids are nearly microscopic.

Output: Some


Input: Consider Input: Sentence1: Heterotrophs get organic molecules from other organisms. 
Sentence2: food contains organic molecules.


Output: molecules