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: Urine leaves the body through a sphincter in the process of urination. 
Sentence2: urine leaves the body upon relaxation of a muscle.

Ex Output:
Urine


Ex Input:
Sentence1: when a river floods , that river deposits soil in flood plains. 
Sentence2: when a river floods, it deposits soil in generally marshy areas.

Ex Output:
deposits


Ex Input:
Sentence1: shelter is used for protection by animals against weather. 
Sentence2: animals use shelter in hot temperatures.

Ex Output:

animals