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: Spikes are forceful the tidal waves of electric current. 
Sentence2: spikes come from tidal energy.

Ex Output:
Spikes


Ex Input:
Sentence1: Sperm pass out of the body through the urethra. 
Sentence2: Sperm travel from the testicles through the vas deferens to the seminal vesicles and the prostate.

Ex Output:
Sperm


Ex Input:
Sentence1: Homeostasis is the chemical equilibrium of the body. 
Sentence2: hormones control many cell activities and are important in the chemical equilibrium of the body.

Ex Output:

body