Aff(x)tion -f(x) unofficial fanclub name

f(x) (에프엑스) is a five member South Korean girl group formed by SM Entertainment in 2009. The name is a play on the mathematical notation for function. The f stands for flower and the x represents the female's double x chromosome. f(x) strives to be the kind of girl group that can change and adapt to many situations.[citation needed] The group members have also been nicknamed "function girls". The group made their debut on September 1, 2009 with release of a digital single "La Cha Ta" (stylized as "LA chA TA"). The quintet consists of Victoria, Amber, Luna, Sulli and Krystal.