with "Twins (Knock Out)", "You Are the One", and three additional tracks were released online on November 8, followed by the release of their debut album Twins on December 6, 2005. The album sold 28,536 copies in the first month of release and debuted at number three in the monthly chart of December 2005. 2006–2007: U, Don't Don, and commercial success In February 2006, Super Junior 05 began performances for "Miracle", the second promotional single from their debut album. "Miracle" topped the music charts of Thailand, drawing interest from international markets. They were subsequently invited to perform at the Pattaya Music Festival in Thailand in March 2006, making it their first overseas gig. As promotions for "Miracle" ended, SM Entertainment began selecting new members for Super Junior's second generation, Super Junior 06. The company even prepared a list of chosen members that were to graduate from the group. However, the company abandoned the rotational concept after adding a thirteenth member, Kyuhyun, in 2006. The group then became known as just Super Junior, without the suffix "05". After the addition of Kyuhyun, Super Junior released their single "U" for free download on May 25, 2006, on their official website. "U" exceeded 400,000 downloads within five hours of release and ultimately surpassed 1.7 million downloads, crashing the server. The physical single of "U" with a total of three tracks was released on June 6, eventually selling over 81,000 units in South Korea. The single became one of Korea's most popular songs of the year, taking up number one spots for five consecutive weeks on two of Korea's top music programs. By the end of the year, Super Junior collected over seven awards in five of South Korea's top music award ceremonies, and was one of the three Best Newcomer winners at the 21st Golden Disk Awards. In late 2006, Kyuhyun, Ryeowook, and Yesung formed the subgroup Super Junior-K.R.Y., Super Junior's first sub-unit. They performed their first single "The One I Love", theme song to the Korean television drama Hyena, on the KBS music program Music Bank on November 5, 2006. In February 2007, Leeteuk, Heechul, Kangin, Sungmin, Shindong and Eunhyuk formed Super Junior-T, a trot-singing group. They released their first single "Rokkugo" on February 23, 2007, and made a debut performance on Popular Songs two days later. Super Junior's second official album was intended for a late 2006 release, but due to