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: June Summer Triangle Three bright stars light up the summer sky. 
Sentence2: Nuclear reactions in stars cause them to brighten up the summer sky.

Ex Output:
bright


Ex Input:
Sentence1: Flies are insects with two wings. 
Sentence2: Flies are arthropods with two wings.

Ex Output:
Flies


Ex Input:
Sentence1: chlorophyll is used for absorbing light energy by plants. 
Sentence2: Soemthing that makes plants green is used for absorbing light energy by plants.

Ex Output:

absorbing