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: Flatworms Flatworms or Platyhelminthes include flukes, tapeworms, and turbellarians. 
Sentence2: Tapeworms belong to the phylum Platyhelminthes.

Output: tapeworms


Input: Consider Input: Sentence1: if an object is made of a material then that object has the properties of that material. 
Sentence2: An object is an item in the real world.

Output: object


Input: Consider Input: Sentence1: Fungi lack chlorophyll, so they cannot make food by photosynthesis as plants can. 
Sentence2: yeast lack clorophyll.


Output: chlorophyll