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: Streams may start with runoff or water seeping out of a spring. 
Sentence2: streams may start with runoff or h2o seeping out of a spring.

Output: Streams


Input: Consider Input: Sentence1: Viruses are parasites of cells. 
Sentence2: Populations of viruses do not grow through division because they are parasites.

Output: are


Input: Consider Input: Sentence1: Controlled experiments are essential for scientific inquiry. 
Sentence2: Scientific inquiry is often done in a lab.


Output: inquiry