In this task, you're given a statement, further information available on a particular linked term from the statement, and a question. Your job is to generate the answer to the question by using the information provided. If there is no clear answer obtainable, output 'none'.

Context: The fourth single to be released off the album was Grayscale's cover of Love Yourself originally performed by Justin Bieber, it was released on July 19, 2017 after the official release of Punk Goes Pop Vol. 7. Link Information: The song was released as a promotional single on November 9, 2015 Question: How many years after the original was released was the cover of Justin Bieber's song released?
Answer: 2