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: Nitrogen is found in proteins, nucleic acids, and chlorophyll. 
Sentence2: Lawns eat nitrogen.

Ex Output:
Nitrogen


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: Female gametophytes produce eggs inside the ovaries of flowers. 
Sentence2: Female gametophytes produce eggs inside the fruit of flowers.

Ex Output:

Female