They won on music bank nine weeks in a row. that is 2 months.
Weekly Win Timeline
January 16, 2009: 1st win
January 23, 2009: 2nd win (absent)
January 30, 2009: 3rd win (January monthly champion / Triple Crown)
February 6, 2009: 4th win
February 13, 2009: 5th win
February 20, 2009: 6th win...