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: Endospores are commonly found in soil and water.
Sentence2: Some bacteria form resistant cells called endospores.

Output: Endospores

Input: Consider Input: Sentence1: Soil Erosion Soil erosion is a natural process.
Sentence2: wind and rain is a natural process.

Output: natural

Input: Consider Input: Sentence1: when water freezes , that water expands.
Sentence2: Water expanding can cause pipes to burst.
Output: expands