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: if an organism becomes too hot then that organism may die. 
Sentence2: a plant can collapse if it gets too hot.

Output: hot


Input: Consider Input: Sentence1: a switch is used to start the flow of current in an electrical circuit. 
Sentence2: lights are on when there is flow of current in an electrical circuit.

Output: circuit


Input: Consider Input: Sentence1: Fertilization occurs when a sperm and an egg fuse. 
Sentence2: fertilization occurs with the formation of the embryo.


Output: Fertilization