In what year was the album “U” released by 슈퍼주니어?

In what year was the album “U” released by 슈퍼주니어?: The album “U” was released in 2006 by 슈퍼주니어, featuring 3 tracks.
What is the most successful song from the album “U” by 슈퍼주니어?: “U” is the biggest hit from the album “U” by 슈퍼주니어.

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