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: Muscles can only contract. 
Sentence2: Contraction is a type of movement.

Output: contract


Input: Consider Input: Sentence1: the emission of sulfur dioxide causes acid rain. 
Sentence2: Sulfur dioxide emissions causes soil nutrients to be leached away.

Output: dioxide


Input: Consider Input: Sentence1: Microorganisms associated with foods. 
Sentence2: Food can cause infections.


Output: foods