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: bacteria cause food to spoil. 
Sentence2: Food poisoning occurs when spoiled food is eaten.

Ex Output:
spoil


Ex Input:
Sentence1: friction causes the temperature of an object to increase. 
Sentence2: pressure causes the temperature of an object to increase.

Ex Output:
causes


Ex Input:
Sentence1: An ordinary ice road is therefore severely damaged by cracks induced by the traffic. 
Sentence2: Ice wedging causes ice roads to be severely damaged.

Ex Output:

damaged