ref: 5f1b70f437ed4f598f9439e201f1f7644f5ce7b5
dir: /sys/games/lib/sudoku/boards/medium-2005-03-28.su/
17....8.. ..65..... 45...8... .1..7...2 ..42.93.. 2...1..6. ...9...58 .....67.. ..2....41 179462835 826531974 453798126 915673482 684259317 237814569 361947258 548126793 792385641