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: Here, the lungs supply the blood with oxygen.
Sentence2: Brain cells die quickly if their blood supply is cut off.

Output: blood

Input: Consider Input: Sentence1: Dinosaur bones, like many other artifacts, are fossilized.
Sentence2: radioactive dating is used to determine the age of dinosaur bones.

Output: Dinosaur

Input: Consider Input: Sentence1: All viruses consist of RNA or DNA and a protein coat.
Sentence2: viruses have RNA.
Output: RNA