Definition: 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.
Input: Sentence1: For a scientist, water is H2O whether from the Ganga or a tap. 
Sentence2: treating H2O is used to remove harmful substances before drinking.

H2O