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: Basically the process is pretty simple. 
Sentence2: All cells share some of the same structures and simple processes.

Output: process


Input: Consider Input: Sentence1: Fission is a type of reproduction, but a baby is the result of sexual reproduction. 
Sentence2: the fallopian tubes are used to make babies.

Output: baby


Input: Consider Input: Sentence1: darkness has a negative impact on photosynthesis. 
Sentence2: darkness has an impact on the energy the sun releases.


Output: darkness