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: Landslides Seismic vibration is a common triggering mechanism for landslides. 
Sentence2: Erosion can cause seismic vibrations which are triggering mechanisms.

Ex Output:
Seismic


Ex Input:
Sentence1: Interest in fossils is worldwide. 
Sentence2: paleontologists study something with worldwide interest.

Ex Output:
Interest


Ex Input:
Sentence1: Interest in fossils is worldwide. 
Sentence2: paleontologists study something with worldwide interest.

Ex Output:

Interest