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.

Ex Input:
Sentence1: if an object is made of a material then that object has the properties of that material. 
Sentence2: items properties are the same as the materials the item is made of.

Ex Output:
made


Ex Input:
Sentence1: if soil is permeable then water easily flows through that soil. 
Sentence2: if soil is permeable then h2o easily flows through the soil.

Ex Output:
flows


Ex Input:
Sentence1: Infancy is the period of most rapid growth after birth. 
Sentence2: development is rapid in childhood.

Ex Output:

rapid