ref: 5fc5c18208546c77f2c279f7f6acf6b01a2d2645
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