1 => 0
   2 => 0
   3 => 1
   4 => 1
   5 => 1
   6 => 1
   7 => 2
   8 => 2
   9 => 2
  10 => 2
  11 => 3
  12 => 4
  13 => 3
  14 => 3
  15 => 2
  16 => 2
  17 => 2
  18 => 1
  19 => 1
  20 => 0
  21 => 0
  22 => 0
  23 => 0
  24 => 0
  25 => 0