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: a camera is used for recording images. 
Sentence2: a camera is used for recording binary.

Output: camera


Input: Consider Input: Sentence1: Plants use unsaturated fatty acids to store energy. 
Sentence2: Plants and fish contain fatty acids.

Output: Plants


Input: Consider Input: Sentence1: Zooplankton are tiny animals that feed on phytoplankton. 
Sentence2: Most copepods feed on phytoplankton.


Output: phytoplankton