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: An organism can gain energy by assimilation or absorption of food. 
Sentence2: Organisms require food for growth.

Ex Output:
food


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: Saliva contributes more than 70 percent of the liquid in the rumen. 
Sentence2: Food is easier to chew because it is moistened by liquid.

Ex Output:

liquid