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: Similarly, stars are referred to as suns, but our star is the Sun. 
Sentence2: our star causes water to evaporate more quickly by adding heat.

Ex Output:
our


Ex Input:
Sentence1: keeping food cold is used for keeping food fresh. 
Sentence2: Keeping food at 40 degrees F or lower is used for keeping food fresh.

Ex Output:
food


Ex Input:
Sentence1: pasteurization reduces the amount of bacteria in milk. 
Sentence2: Pasteurization reduces the amount of unicellular organisms in milk.

Ex Output:

amount