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: if fossils of an animal or plant are found in a place then that animal or plant used to live in that place. 
Sentence2: Fossils are preserved original remains or preserved evidence of plants and animals.

Output: fossils


Input: Consider Input: Sentence1: if fossils of a water animal or plant are found in a place then that place used to be covered by water in the past. 
Sentence2: Fossils are the remains of prehistoric life.

Output: fossils


Input: Consider Input: Sentence1: burning wood is used to produce heat. 
Sentence2: Food is cooked by the steam and heat.


Output: heat