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: Electrical currents cause magnetic fields. 
Sentence2: Electrical currents can cause objects to repel each other.

Ex Output:
Electrical


Ex Input:
Sentence1: Asbestos is a dangerous carcinogen. 
Sentence2: Asbestos causes cancer.

Ex Output:
Asbestos


Ex Input:
Sentence1: erosion causes a river to become deeper and wider. 
Sentence2: Fertile topsoil is then lost in erosion.

Ex Output:

erosion