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: Antigens are proteins foreign to the body. 
Sentence2: antigens are proteins.

Output: proteins


Input: Consider Input: Sentence1: Warm temperatures have helped plant growth and sizing. 
Sentence2: a greenhouse helps  plant growth.

Output: growth


Input: Consider Input: Sentence1: when an electrical circuit is working properly , electrical current runs through that circuit. 
Sentence2: When an electrical circuit is working properly , electric charge runs through that circuit.


Output: circuit