ref: 69cd42bb94c4454c8478eae8a61c5fec9e16ebb7
dir: /sys/games/lib/sudoku/boards/medium-2005-04-12.su/
.62.....1 ...4.6..8 .5..21... ...8...37 ....5.... 42...3... ...31..5. 6..9.4... 2.....49. 962538741 173496528 854721369 516849237 398257614 427163985 749312856 635984172 281675493