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: Genetics is the study and application of principles of inheritance to plants and animals . 
Sentence2: Pedigrees are useful tools for studying Genetics.

Output: Genetics


Input: Consider Input: Sentence1: cold fronts cause thunderstorms as they pass by. 
Sentence2: Cold fronts cause lightning.

Output: cold


Input: Consider Input: Sentence1: a warm front causes cloudy and rainy weather. 
Sentence2: Warm air advancing on cold air causes cloudy and rainy weather.


Output: causes