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: Angiosperm sporophyte is dominant. 
Sentence2: Flowers form on angiosperms.

Output: Angiosperm


Input: Consider Input: Sentence1: natural magnetism is used for pointing north by a compass. 
Sentence2: For the ordinary compass, align to the North direction.

Output: north


Input: Consider Input: Sentence1: Osteoporosis is a disease in which osteoclasts are more active than osteoblasts. 
Sentence2: a thinning and weakening of bone is a disease in which osteoclasts are more active than osteoblasts.


Output: active