Jessica – Main vocals, Background vocals Sunny – Lead vocals Tiffany – Lead vocals Hyoyeon – Vocals Yuri – Lead vocals Sooyoung – Vocals Yoona – Vocals Seohyun – Lead vocals, Background vocals Miles Walker – producer, mixing and programming Fredrik Thomander – songwriter Johan Becker – songwriter Junji Ishiwatari – songwriter, translation Tom Coyne – mastering Charts Weekly charts Year-end charts Sales and certifications Release history References External links 2012 singles 2012 songs Girls' Generation songs Japanese-language songs SM Entertainment singles Billboard Japan Hot 100 number-one singles Songs written by Junji Ishiwatari Songs written by Fredrik Thomander