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: Consider Input: Sentence1: Results can be damaging or disastrous. 
Sentence2: Lack of immunization can be damaging or disastrous.

Output: damaging


Input: Consider Input: Sentence1: erosion of soil has a negative impact on the environment. 
Sentence2: erosion of soil has a negative impact on forests.

Output: erosion


Input: Consider Input: Sentence1: Development means to get better, growth means to get bigger. 
Sentence2: Infancy is the period of most rapidly getting bigger after birth.


Output: bigger