c :: [0,2,8,7,5,3,1,9,4,6,
      2,0,6,7,3,3,1,7,2,4,
      8,6,0,8,3,9,7,9,4,6,
      7,7,8,0,8,8,6,4,9,11,
      5,3,3,8,0,6,4,6,1,3,
      3,3,9,8,6,0,2,10,5,6,
      1,1,7,6,4,2,0,8,3,5,
      9,7,9,4,6,10,8,0,5,7,
      4,2,4,9,1,5,3,5,0,2,
      6,4,6,11,3,6,5,7,2,0]