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: Conventional myosin is required for cytokinesis . 
Sentence2: Conventional myosin is required for the final stage of cell division.
Example Output: Conventional

Example Input: Sentence1: With a spatula, fold in flour mixture. 
Sentence2: a sifter is used for separating flour.
Example Output: flour

Example Input: Sentence1: Basic unit of the plant body is the cell. 
Sentence2: Basic units of the plant body vary in size as well as shape, but all are very small.
Example Output:
Basic