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.

Ex Input:
Sentence1: Refrigerators are major users of electricity. 
Sentence2: Keeping food fresh for a long period of time requires a lot of electricity.

Ex Output:
electricity


Ex Input:
Sentence1: Translation reads the genetic code in mRNA and makes a protein. 
Sentence2: Nucleotide sequences are read in mRNA and a protein is made.

Ex Output:
mRNA


Ex Input:
Sentence1: Ants communicate with chemicals called pheromones. 
Sentence2: Ants communicate with semiochemicals.

Ex Output:

Ants